(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Radio Electronics (September 1991)"

;> 48783 



rECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE 

UILD THIS I 

E5LA COIL 

enerate spectacular displays 

/ith our solid-state version of 

classic high-voltage project! 

UDIO-FORMAT 
ONFUSION 

Jetails on Sony's Mini Disc 

nd Philips' 

^igital Compact Cassette 



UILD OUR 
IICRO-ANALYZER 

md start repairing microwave 
ivens today! 

UILD A SPECTRUM 
NALYZER 

let professional quality for a 
raction of what you might 
ixpect to pay 






HONE-LINE SENTINEL 

_uild our telephone 
ne-in-use monitor 

LECTRIC PHENOMINA 

^n intuitive look at 
ilectromagnetic theory 



$2.95 U.S. 
$3.75 CAN 












♦ 



• ' ♦ 



FLUKE AND PHILIPS - THE GLOBAL ALLIANCE IN TEST & MEASUREMENT 



FLlllK 




7 SERIES II 



8 New Meters. 8 Old-Fashioned Values. 



Introducing Fluke's 70 Series II, next- 
generation multimeters that meet the 
increasing demands of your job and your 
budget. 

Consider. At the top of the line, the new Fluke 
79 and 29 deliver more high-performance 
features - capacitance, frequency, a fast 63- 
segment bar graph.lo-Ohms range, Smooth- 
ing™, faster ranges - than DMMs costing 
much more. 

At the entry level, the new model 70, Fluke's 
lowest-priced DMM ever, delivers unparalleled 
Fluke quality at a price comparable to "dispos- 
able" meters. 

And in between are all the models that have 
made the 70 Series the most popular DMM 
family in the world - updated, refined and 
delivering even more value than ever. 



"BASICS" REDEFINED 

No matter which 70 Series II you choose, you 
get simple, one-handed operation. High 
resolution. And built-in, go anywhere reliability. 

Automatic Touch Hold® - standard on every 
model - locks the reading on the display and 
signals you with a beep, automatically updating 
for each new measurement without a reset. 
Leaving you free to concentrate on your work, 
not on your meter. 

YOUR BEST CHOIC E 

Best of all, every 70 Series II is a Fluke, backed 
by a worldwide service network and an industry- 
leading 3 year warranty. 

So the next time you're in the market for a new 
meter, ask for the one that guarantees old- 
fashioned value. Fluke 70 Series II. For more 
information call 1-800-6789-L1T. Or call 
1-800-44-FLUKE, ext 33 for the name of your 
nearest Fluke distributor. 

CIRCLE 121 ON FREE INFORMATION CARD 



Fluke 79 Series II & 29 Series II 



S185" 



13011 Count Digital Display (9998 in Hi &-H- ) 



63 segment Aialng Bsr G r api 



0.3% Basis DC Voltane Accuracy 



Automatic Touch Hold 1 



D ; ods Tesl, Atdible Continuity Beepef 



Aultjfanoino Mama Ra<"arg 



Holster with Flei Slarnj Tl 



Frequency Counter to over ?Q kHz 



Capac lance 10 pf to 9999uf 



Lo-0hms Range wiih Zero Calibraliun 



Smoothing 1M 



TO Houts Battery tile (ilia rt 



3 year Warranty 



79/7WS/73/70 lot measurements to 4800 V A. 



29ff3<21 lot higher energy measurements 



'Flute 70 Series II suggested U_S list p'ices targe 'mtr $63 !c JIBS 

John Fun Wig Co In: PD BoiSCKM/SISOEElM WA9J2D5U5 . 206 als-HOO 
Canana4l6-BM-7KW aiflerCDunf.es 2&5.3M-&M CCapyritfit 1931 John flute Mta 
Co int ah j^his itseved Ad no 00091 Prices and spscir^hans subject to ctwipe 



FLUKI 



September 1991as5 



'EEtnmics 



33 SOLID-STATE TESLA COIL 

With a 100,000-volt peak output, this Tesla coil can create 8-inch 

sparks! 

Duan A. Bylund 

40 SPECTRUM ANALYZER 

This month we give construction details and discuss the software for 

our PC-based tool. 

Dan Doberstein and John Cardone 

47 BUILD THE MICROANALYZER 

This instrument makes it easy to repair microwave ovens! 
David T. Miga, GET 

60 PHONE LINE SENTINEL 

You won't be interrupted by people carelessly picking up an 
extension if the Sentinel is at work. 
Daniel B. Cooper 



tJ^H.'I.IH.IrV 




57 AN INTUITIVE LOOK AT ELECTROMAGNETIC THEORY 

An explanation of electric phenomena 
William P. Rice 

63 AUDIO-FORMAT CONFUSION 

DAT, DCC, Mini Discs — Where does the future of audio lie? 
Brian C. Fenton 



IMiil 



6 VIDEO NEWS 

What's new in this fast- 
changing field. 
David Lachenbruch 

18 EQUIPMENT REPORTS 

R.L. Drake R8 world band 
shortwave receiver, 

67 HARDWARE HACKER 

Phone caller ID, and more, 
Don Lancaster 



74 AUDIO UPDATE 

Futureproducts. 
Larry Klein 

80 COMPUTER 
CONNECTIONS 

MS-DOS 5.0. 
Jeff Holtzman 



Vol. 62 No. 9 




BUILD THE 

MICROANALYZER 



wrt* M* tRHt+vair*" 



PAGE 47 



C3 : I (/> 




PAGE 63 




96 Advertising and Sales 
Offices 




96 Advertising Index 




12 Ask RE 




16 Letters 




83 Market Center 




26 New Lit 


m 

TO 


22 New Products 


m 


4 What's News 


m 




to 





CO 
O 

o 

EC 

r- 

o 

LU 



o 

5 
< 
cc 



Ever since Nikola Tesla created 
the first one about a century ago, 
Tesla coils have been popular proj- 
ects for electronics hobbyists and 
students. There are a couple of rea- 
sons for their continued popularity: 
One is that they create a dazzling 
electrical display, and the other is 
that there is much to be learned 
about electronics by building a Tesla 
coil. Our solid-state Tesla coil is dif- 
ferent from the classic one in that 
the coupling to the secondary coil is 
by a direct electrical connection 
rather than by magnetic fields. It's 
the same in that it creates a spark as 
long as 8 inches and makes an ex- 
cel lent teaching tool. To find out how 
to build your own solid-state Tesla 
coil, turn to page 33. 




»:**.-:i').'" 



THE OCTOBER ISSUE 

GOES ON SALE 

SEPTEMBER 5 



BUILD AN ENERGY CONSUMPTION MONITOR 

Are your electric bills sky-high? Keep tabs on how much your appliances 
cost to run with the Energy Consumption Meter. 

BUILD A DIRECT DIGITAL SYNTHESIZER 

Generate low-distortion sinewaves digitally! 

BINAURAL BANTER 

A look at the technique that makes recordings come alive. 

AN INTUITIVE LOOK AT ELECTROMAGNETIC THEORY 

Part 3: The magnetic field. 

As a service to readers, RADIO-ELECTRONICS publishes available plans or information relating to newsworthy products, 
techniques and scientific and technological developments. Because of possible variances in the quality and condition of 
materials and workmanship used by readers, RADIO-ELECTRONICS disclaims any responsibility for the safe and proper 
functioning of reader-built projects based upon or from plans or information published In this magazine. 

Since some of the equipment and circuitry described in RADIO -ELECTRONICS may relate to or be covered by US- patents, 
RADIO-ELECTRONICS disclaims any liability for the infringement of such patents by the making, using, or selling of any such 
equipment or circuitry, and suggests that anyone interested in such projects consult a patent attomey- 

RADIO-ELECTRONICS. (ISSN 0033-7862) September 1991. Published monthly by Gemsback Publications. Ine .. 500-B Bi- 
County Boulevard. Farmingdale. NY 11735 Second-Class Postage paid at Farmingdale. NY and additional moiling offices. 
Second-Class mail registration No, R125166280, authorized at Toronto, Canada- One-year subscription rate U.S.A. and 
possessions $17-97, Canada $25. 65 (includes G.S.T. Canadian Goods and Services Tax Registration No. R1 25166280). all other 
countries S26.97. All subscription orders payable in U.S.A. funds only, via international postal money order or check drawn on a 
U.S.A. bank- Single copies $2-95- c 1991 by Gemsback Publications. Inc. All rights reserved. Printed in USA 

POSTMASTER: Please send address changes to RADIO-ELECTRONICS, Subscription Depl . Box 55115. Boulder. CO 
80321-5115. 

A stamped self-addressed envelope must accompany all submitted manuscripts and/or artwork or photographs if their return is 
desired should they he rejected. We disclaim any responsibility for the loss or damage of manuscripts and/or artwork or 
photographs while in our possession or otherwise. 




ettillllni 
ECtrDfJMES 



Hugo G e msback (1884- 1 967] founder 

Larry StecMar, EHF. CET. 
edttor- in -chief and publisher 

EDITORIAL DEPARTMENT 
Brian C. Fertton, editor 
Marc Spiwak, associate editor 
Kim Dunleavy, 

assistant technical editor 
Teri Scoduto, assistant editor 
Jeffrey K. Hoftzman 

computer editor 
Robert Grossblatt. circuits editor 
Larry Klein, audio editor 
David L&chenbruch 

contributing editor 
Don Lancaster 

contributing editor 
Kathy Teronxi. editorial assistant 

ART DEPARTMENT 
Andre Duzant, art director 
Injae Lee, illustrator 
Russell C. Truelson, illustrator 

PRODUCTION DEPARTMENT 
Ruby M. Y*t>, production director 
Janice Box, 

editorial production 
Karen S. Brawn 

advertising production 
Marceila Amoroso 

production assistant 

CIRCULATION DEPARTMENT 
Jacqueline P, Cheese bore 

circulation director 
Wendy Alanko 

circulation analyst 
Theresa Lombardo 

circulation assistant 
Michele Torrillo, reprint bookstore 

Typography by Mates Graphics 
Cover photo by Diversified Photo 
Services 

Radio-Electronics is indexed in 
Applied Science t Technology Index 
and Readers Guide to Periodical Liter- 
ature. 

Microfilm & Microfiche editions are 
available. Contact circulation depart- 
ment for details- 
Advertising Sales Offices listed 
on page 00. 
Radio -Electronics Executive and 

Administrative Offices 

1-5.6-293-3000. 
Subscriber Customer Service: 

1800 2880652. 
Order Entry for New Subscribers: 

1800-999 7139. 



V^***' Bureau 
oi G-rcutalion 



TEST FOR LESS 
WITH FORDHAM 

Special Bonus with 
any order 




Now Only 

195 



Rugged & Reliable, 
•8 Functions 
•37 Ranges 



scope Hand Held 
Digital Multimeters 



Model 
DVM-638 

Now only 

w 



• 11 Functions 
•38 Ranges 
•Continuity Beeper 

• Overload Protection 

Optional Carrying 
Case CA-92 $9.95 




RD-2110 Radar Detector 

Yours CJIA95 



for only 



<5><3 



m 



Reg. 109.95 



bra' 



Feature Packed' 
Contemporary Look' 



with your order of any item on 
this page. 




SCOPE 

v/i Digit 



lcr Meter 

Ideal for field applications! 

•Light weight • Portable *Hand Held 
•Overload Protecton •Test Leads 

Model LCR-680 x 

SALE *119 ,s 

Optional Carrying Case CA-92 $9.95 



SCOPE 
Vh Digit 



LCD Meter 

■0.5% Accuracy • DOAC voltage, DC Current 
•Diode & Battery Test •Overload Protection 
DC 500V, AC 350V, Ohms 250V DOAC 
Model DVM-630 

SALE *32 50 

Optional Deluxe Carrying Case CC-50 $4.50 



$50,00 




Sweep Function Generator 

Sale! now W 



Reg. $319.95 

MOdel FG-801 

•Selectable Wave 
& TTL Pulse 
• 7 Frea Ranges 

(0.2 Hz to 2MHz) 
•Sweep Ratio 1004 




scope Analog Lab 



Sale! Now W° 



Reg. $225.00 



Model sc-6000 

• SFreq. Ranges 
•Variable Positive 
Power 
•Potentiometer 




Proto-Board Station 

Special! $ 298° 



Model sc-goooA 

• 3 Wire AC Line Input 

• Function Generator 
•Triple Rawer Supply 
•S Logic LED's 







Feature Packed! Hitachi Oscilloscope 



NOWV* 

Reg. S615.0O 

Model v-212 Dual Trace 

•DC to 20 MHz, imVfliv 
•6" Rectangular Screen 
PROBES INCLUDED! 






•- 



»? 



i 

j.6 



g_8 8^_ 




HITACHI Dual Trace Oscilloscope 

NOW $ 598 00 



Best value! 



Model v-355 

•19 Calibrated Sweeps 
•6" CRT •Auto Focus 
PROBES INCLUDED! 




Fordham 

?60 Motor Parkway, Hauppauge, New York 11788 



ASK FOR YOUR FREE CATALOG 

TOlL 800-695-4848 



FREE 



flharn 1991 Offers '. -:■ 



I (iOOi Money orders, checks accepted 
I fZxyl CQD's require 25% deposit 



Service & Shipping Charge Schedule 

Continental U.S.A. 
FOR ORDERS ADD FOR ORDERS ADD 



$0-25. 
$26-50 . 
$51-100.. 

$101-200 
$201-300 

$301-400 
S401-5W 



$4.50 
. $6.00 
..$7.50 
$900 
$10.00 
.$12.00 
.$14.00 



$501-750 $16.00 

$751-1,000 $16.00 

$1,001-1,250 ...$20.00 
$1,251-1,500 ..$22.00 

S1.501-2.000 S2750 

$2,001 and up.. $35.00 



■ 



A review of the latest happenings in electronics. 



CO 

O 



o 

Q 
< 



ISCET certifies 30,000th 
technician 

When Robert Bruce Bottoms, a 
computer technician and evening- 
school engineering major, achieved 
journeyman-level certification spe- 
cializing in computers , he became the 
30,000th electronics technician to be 
certified by the International Society 
of Certified Electronics Technicians 
(ISCET), Fort Worth, TX. The 28-year- 
oid United Parcel Service employee 
has worked in information services, 
industrial engineering, weight and 
balance, and programming. Bottoms 
also served as project technician for 
the introduction of the delivery infor- 
mation acquisition device, a hand- 
held microcomputer that is replacing 
paperwork for UPS drivers. 

The computer specialty exam 
covers the operation of computer 
systems with an emphasis on hard- 
ware. Subject areas include basic 
arithmetic and logic operations as re- 
lated to computer theory, computer 
organization, input and output equip- 
ment, and memory and storage; 
knowledge of software, program- 
ming, and troubleshooting is also re- 
quired. The computer exam, and 
others offered by ISCET, have be- 
come the standards by which deal- 
ers, manufacturers, and government 
agencies distinguish the most knowl- 
edgeable technician from the rest. To 
become a member of ISCET, techni- 
cians must pass the basic GET exam. 
Other certification exams are offered 
by ISCET in such specialty areas as 
consumer, industrial, communica- 
tions, FCC Legal, computer, audio, 
medical, radar, and video electronics. 
Information about ISCET is available 
from ISCET, 2708 West Berry Street, 
Fort Worth, TX 76109. 

Semiconductor process 
precisely controls crystal 
growth 

An experimental process de- 
veloped by Bellcore (Red Bank, NJ) 
has produced aluminum gallium arse- 
nide crystals that are compositionally 
ten times more precise than any pre- 
viously reported. The process offers 
the first practical method to monitor 



and control the growth of compound 
semiconductor alloys — which could 
significantly increase a manufac- 
turers' ability to mass produce com- 
pound semiconductor devices and, in 
turn, reduce prices. 

Bellcore's approach uses optical 
signals to provide information about 
the chemical development of a crys- 
tal surface while the crystal is being 
grown, instead of analyzing crystal 
growth after the process is complete, 
as in current fabrication techniques. 
Ellipsometry, an optical technique 
that bounces light off a crystal's 
emerging surfaces, reveals intricate 
details. Findings are instantaneously 
fed into a computer and analyzed. 
Within seconds, the computer uses 
the information to regulate the flow of 
materials into the growth chamber, so 
that small errors in material composi- 
tions are corrected as they occur. The 
Bellcore research team calls the sus- 
tained precision level of 0.1% that 
they have achieved "an important 
milestone in the quest for con- 
sistently perfect' aluminum gallium 
arsenide crystal structures." 




BELLCORE RESEARCHER BILL QUINN 
grows aluminum gallium arsenide crys- 
tals for use in semiconductor materials 
and devices, using an experimental pro- 
cess that corrects small errors in material 
composition as they occur, resulting in 
the world's most precise crystals. 



American technological edge 
over Japan? 

According to the results of a Gallup 
survey reported in the April, 1991 is- 
sue of IEEE Spectrum, a sampling of 
U.S. electrical engineers believes 
that the United States holds a tech- 
nological edge over Japan in many 
areas. The report summarizes a sur- 
vey of a cross section of 150 IEEE 
(Institute of Electrical and Electronics 
Engineers) members consisting of 50 
each from government, industry, and 
academia. The survey, commis- 
sioned by Japan's financial daily pa- 
per, Nihon KeizaiShimbun, asked the 
engineers questions regarding areas 
in which the United States holds the 
technological edge over Japan now 
and whether it is likely to in the future. 
The respondents perceived America 
to be currently ahead in nine out of 
twelve areas: space/aviation, medi- 
cal/pharmaceutical, software, bio- 
technology workstations, supercom- 
puters, personal computers, semi- 
conductorrnicroprocessors. and new 
industrial material. Japan led in con- 
sumer electronics, semiconductor 
memory, and fifth -generation com- 
puters. A large majority of the engi- 
neers polled expected the U.S. to 
maintain its lead in those nine areas, 
despite some anticipated slipping in 
biotechnology and fifth-generation 
computers. 

Those results contrast with recent 
studies by the U.S. Department of 
Commerce and the Council on Com- 
petitiveness, which suggest that the 
U.S.'s current lead in technologies 
will be usurped by Japan by the year 
2001 . However, the article points out 
that some of the discrepancies be- 
tween studies can be explained by 
the fact that a technological lead "is 
not invariably the best indicator of 
marketplace success." 

Asked where future technological 
priorities should be placed, the engi- 
neers supported the development of 
natural energy sources (91 %), optical 
IC's (83%). anti-cancer medication 
(83%), medication for Alzheimer's 
disease (80%), one-billion-bit dynam- 
ic RAM chips (79%), and high-speed 
surface transportation (79%). R-E 



Some Breadboards Cost Less 

Than PROTO-BOARD brand 

They Should. 




proto 

BOARD 



BRAND 




At Global Specialties* we make only one kind of 
breadboard, the very best, PROTO-BOARD* brand. 
American made and guaranteed for life, 

Sure, save a few dollars today. ..buy cheap... but 
remember, you only get what you pay for! Is it really worth 
it??? Ask yourself... Do they perform like PROTO-BOARD' 1 
brand? Are they as reliable? Will they last like a PROTO- 
BOARD* brand? 

How can we guarantee PROTO-BOARD* brand 
breadboard for life unconditionally? Because we control 
every step right in our New Haven factory, and because 
we are obsessed with quality. 

That's why we mold our own plastic and stamp our 
own precision contacts. We even designed our own 
machine to assemble each breadboard to exacting stan- 
dards. Assuring every PROTO-BOARD "brand is built to 

perfection when it leaves our USA factory backed 

by our unconditional "Life-Time" guarantee. 



The others, they arrive from Taiwan. With good 
reason, they are made cheaper! 

So next time you consider a cheaper breadboard, 
think twice. You'll need too, because even after you have 
worn out your second imported 
breadboard our PROTO- 
BOARD ''brand would have still 
been going strong. 

PROTO-BOARD 5 brand. 
The breadboard you only buy 
once. Now which one really 
cost less? 

PROTO-BOARD* brand 

breadboards and the complete 

Global ' line of test instruments 

are in stock at fine electronic 

distributors everywhere. 




Can't Wait! 

Call Toil-Free 

1-800-572-1028 



GLOBAL 
SPECIALTIES 




GLOBAL SPECIALTIES" 

70 Fullon Terrace, New Haven, CT 06512 
co 1991 I me rplex Electronics 
All Global Specialties ■ breadboard ing products 
are made in New Haven Ct. 

A031 



Mnterplex 
/industries 

company 



CIRCLE 190 ON FREE INFORMATION CARD 



What's new in the fast-changing video industry. 



mmHHinm 





Q 
< 



• Widescreen TV for U.S. TV 

sets with the widescreen 16:9 ratio 
are on sale in Europe, with both 
Thomson and Philips introducing 
models (Radio-Electronics. June 
1991), but both companies have been 
reluctant about committing them- 
selves to introduce a similar product 
in the United States because of a lack 
of program material. Now it appears 
that the Japanese manufacturers 
have no such hesitancy, and we could 
see direct-view or projection sets — 
or both — with 16:9 pictures before 
the year is over. 

The first company to commit to in- 
troducing a widescreen TV set here 
was JVC, which showed a prototype 
with a 34-inch tube at the Summer 
Consumer Electronics Show in Chi- 
cago. JVC didn't give any marketing 
date except "soon," but its officials 
stressed that they were showing an 
actual production model, not a pro- 
totype. Like the European wide- 
screen sets, it will accommodate a 
number of picture modes and 
sources. For example, it will show a 
"letterboxed" movie from tape or 
disc full-screen and in proper dimen- 
sion. With a conventional 4:3 picture 
source, it can magnify the image to 
full widescreen by cutting off a small 
portion of the top and bottom, or it 
can show it as a 4:3 picture leaving 
part of the screen blank. Under the 
latter arrangement, it can occupy the 
unused part of the screen with a 
group of pictures from other channels 
("picture outside picture"). 

A race may be shaping up in Japan 
to introduce the first non-HDTV wide- 
screen TV set, with Toshiba and Mit- 
subishi said to be ready to introduce 
sets with 16:9 ratio tubes and Hitachi 
planning a production model. The the- 
ory behind the industry's sudden in- 
terest in widescreen pictures with 
standard resolution is that even when 
HDTV comes it will be at least 10 
years before it dominates the market, 
and in the meantime widescreen re- 
ceivers will become popular as inter- 
im devices. 

• LCD projectors. Projection TV 
sets using liquid crystal devices as 



shutters are getting better all the 
time. Sharp has introduced an indus- 
trial projector with about 650,000 pix- 
el resolution (at an $8,000 list price) 
that finally appears to have achieved 
satisfactory picture quality. 

No sooner had Sharp's model ap- 
peared than Philips announced its 
own model with about the same reso- 
lution but with many new features. It 
actually uses the same Sharp-made 
LCD's, but it will be priced around 
$6,000-$7,000 and aimed at com- 
mercial and industrial customers as 
well as high-end "home theater" 
buyers, according to Philips. 

The Philips set, to be made in Hol- 
land and sold in the United States 
under the Magnavox brand, is a TV 
set complete with tuner — unlike 
other companies' monitor-only sets, 
which require VCR's or other out- 
board tuner systems. It employs a 
Philips-developed metal-halide lamp 
as its light source. The lamp is user- 
replaceable, and an extra lamp is 
packed in the projector. The lamp life 
is claimed to be 2,000 hours, and the 
on-screen graphics include a count- 
down telling the amount of life left in 
the lamp. When there are only 50 
hours to go, a warning signal appears 
on the screen. 

The picture projected by the Philips 
unit may be reversed or turned up- 
side-down for incorporation in rear- 
projection systems. An interesting 
feature is the capability of pointing 
the wireless remote control at the 
screen instead of the projector, be- 
cause of the light collector and ampli- 
fier built into the unit. The projector, 
weighing 38 pounds, has a built-in 
"convenience speaker" as well as a 
10-watt-per-channel amplifier for re- 
mote stereo speakers which can be 
placed at either side of the screen. In 
the future, Philips plans a 16:9 wide- 
screen version, and eventually the 
company predicts a set about the 
size of a VCR. Maximum picture size 
is about 100 inches diagonally. 

• Trumping Sony's ace. Sony 
thought it had everything lined up. It 
was ready to introduce a new CD- 
ROM-based interactive multimedia 



format ("Super Disc") and had 
reached an agreement with Nintendo 
for Sony to supply hardware that 
would also be compatible with Nin- 
tendo's 16-bit Super Nintendo Enter- 
tainment System (SNES). and 
presumably Nintendo and its soft- 
ware licensees would support the 
Super Disc format with CD-ROM 
games. But Sony received a major 
surprise when Nintendo announced it 
had teamed up with Philips in a deal 
under which Nintendo will develop 
software based on the CD-ROM-XA 
format, which is compatible with Phi- 
lips' Compact Disc-Interactive (CD-I) 
Format, and Philips will develop a low- 
cost CD-ROM-XA drive for SNES. 
Sony was completely flabbergasted 
when Nintendo announced that it 
would not support the Sony system 
with software, and that "We will not 
cooperate with Sony." At our dead- 
line, Sony, Nintendo, and Philips were 
in intensive negotiations to resolve 
the three-way dispute. 

• Dual-deck VCR setback. Go- 
Video, the Phoenix. AZ company, 
which sells a dual-deck VCR and 
which sued many Japanese and 
Korean manufacturers alleging con- 
spiracy not to supply it with parts or 
complete equipment, decisively lost 
its first round in federal court. Al- 
though most of the original defen- 
dants settled with Go-Video to avoid 
coming to court, Sony, JVC, and 
Matsushita refused to settle and pre- 
cipitated a court battle involving a jury 
trial. Although the trial in Phoenix last- 
ed two months, the eight-member 
jury took just three hours to decide 
that there had been no conspiracy to 
keep Go-Video out of the dual-deck 
VCR market, Go-Video, which had 
sought at least $500 million in 
damages, said that it would appeal 
the decision. 

Meanwhile, the Go-Video VCR-2 
dual-deck VCR was reduced in price 
from its original $1,000 to about 
$700, and its five-year warranty re- 
duced to one year. Go-Video Chief 
Executive Officer Terren Dunlap testi- 
fied that they sold about 16,000 
decks in the first 11 months. R-E 



Why take chances in 
today's job market? 

Graduate as a fully trained electronics professional. 



To get ahead and stay ahead in today's 
economy, you need the electronics 
training CIE has been providing its 
150,000-plus successful graduates 
with for nearly 60 years. 

Meet the Electronics Specialists. 

When you pick an electronics school, 
you're getting ready to invest time and 
money. And your whole future depends 
on the education you receive in return. 
That's why it makes so much sense 
to go with number one... with the 
specialists... with CIE! 

There's no such 
thing as a bargain 
education. 
If you talk to some 
of our graduates, 
and we recom- 
mend you do, 
chances are 
you'd find a lot 
of them shopped 
around for their 
training. Not for 
the lowest priced, 
hut for the best 
training available. 
They pretty much 
knew what was 
available when they picked CIE as 
number one. 

Because we're specialists we have to 
stay ahead. 

At CIE we have a position of leadership 
to maintain. Here are just a few of the 
ways we hang onto it- 
Pro grammed Learning. 
That's exactly what happens with CIE's 
Auto- Prog rammed Lessons". Each 
lesson uses famous "programmed 
learning" methods to teach you import- 
ant electronics principles. You explore 
them, master them completely, before 
you start to apply them. You thoroughly 
understand each step before you go on 
to the next. You learn at your own pace. 
And, beyond theory, some courses 
come fully equipped with electronics 
equipment to actually let you perform 
hundreds of hands-on experiments. 

Experienced specialists work closely 
with yon. 

Even though you study at home. CIE's 
faculty and staff stand ready to assist via 
CIE's toll free number. And. each time 
you return a completed exam you can 



be sure it will be reviewed, graded and 
returned with the appropriate instruc- 
tional help, you get it fast and in writing 
from the faculty technical specialist best 
qualified to answer your question in 
terms you can understand. 

Pick the pace that's right tor you. 

CIE understands people need to learn at 
their own pace. There's no pressure to 

keep up. ..no slow learners hold you back. 
If you're a beginner, you start with the 
basics. If you already know some electro- 
nics, you move ahead to your own level. 

"Same Day" 
grading cycle. 

When we 
receive your 
lesson, we 
grade it and 
mail it back the 
same day. You 
find out quickly 
how well you're 
doingl 

State-ol-the-art 

laboratory 

equipment. 

Some courses 
feature the CIE 
Microprocessor 
Training Laboratory. An integral part of 
computers, microprocessor technology 
is used in many phases of business, 
including service and manufacturing 
industries. The MTL gives you the 
opportunity to program it and interface it 
with LED displays, memory devices and 
switches. You'll gain all the experience 




needed to work with state-of-the-art 

equipment of today and tomorrow. 

Hew Courses! 

CIE now offers two new career courses: 

Automotive Electronics and Computer 

Operation and Programming. 

CIE otters you an Associate Degree. 
One of the best credentials you can have 

in electronics — or any other career field 
— is a college degree. That's why CIE 
offers an Associate in Applied Science 
in Electronics Engineering Technology. 
And all CIE career courses earn credit 
toward your degrees. 

Which CIE training fits you? 

Beginner? Intermediate? Advanced? 
CIE home study courses are designed 
for ambitious people at all entry levels. 
People who have: No previous 
electronics knowledge, but do have 
an interest in it; Some basic knowledge 
or experience in electronics: In-depth 
working experience or prior training in 
electronics. 

At CIE you start where you fit and 
feel comfortable where you start, then go 
on from there to your Diploma, Associate 
Degree and career! 

Today is the day. Send now. 
Fill in and return the postage-paid card 
attached. If some ambitious person has 
already removed it, cut out and mail the 
coupon below. You'll get a FREE CIE 
school catalog, plus complete informa- 
tion on independent home study. Mail 
in the coupon below or, if you prefer, 
call toll-free 1-800-321-2155 [in Ohio, 
1-800-523-9109). 



I □ YES! I want to get started. Send me my CIE school catalog including details 

I 

I 



AE23 



about the Associate Degree program. (For your convenience, CIE will have a 
representative contact you — there is no obligation.) 



Prim Name 
Address — 

City 

Age 



Apt. 



Area Code/Phone No.(_ 



State 
-> — 



.Zip. 



I Check box for G.I. Bulletin on Educational Benefits D Veteran O Active Duty 

warn 



1 ///r»rr3^TUTE N s F /^s **&#&**»&. 

I llllkmZi I I Fl F CTRONICS, INC 3 Tgi T | A class ofoTiS, 

JTTGEmst tTth Street* CTevetand. OfrtQ441J4*{?16t ?Bh940Q \ ^"^1 £ 



>/ Since 1934. 



cc 
m 



S 

CD 

m 

3J 



SELECT 5 
10 * only $4 

Allies to « 11n 




noHS 

ELECTRONICS 

FIX-IT BOOK 



3414 £39.95 
Counis as 2 



2S83P SI 8. 95 




ElKTROSTATK 

DISCHARGE 

PROTECTION 




261 3P S17.S5 



MJUMIKS 

MSJKittHli 




3107P S18.95 





-'—*■—' 1 

master 




IC 




t(KlKHI»>N 





3656P S17.95 



THE CIAKT BOUl Of 

ELECTRONICS 

PROJECTS 





MASTTFI 

w 

tLCCTHQMIC 

owDrn 





Z^ 



3329 $29.95 
Counts as 2 




CO 
O 

^ 
o 

£ 

o 



a 
o 
g 

8 




Your most complete source for electronics books 

for over 25 years. 






An Absolutely No-Risk Guarantee. 

v *~ ! ^___^_i 




Membership Benefits * Big Savings, tn addition to 
this introductory offer, you keep saving substantially with 
members' prices of up to 50% off the publishers' 
prices. • Bonus Books. Starting immediately, you will be 
eligible for our Bonus Book Plan, with savings of up to 80% 
off publishers' prices. • Club News Bulletins. 15 times 
per year you will receive the Book Club News, describing 
all the current selections— mains, alternates, extras— plus 
bonus offers and special sales, with scores of titles to 
choose from, * Automatic Order. If you want the Main 
Selection, do nothing and it will be sent to you automatical- 
ly. If you prefer another selection, or no book at all, simp- 
ly indicate your choice on the reply form provided. You will 
have at least 1 days to decide. As a member, you agree 
to purchase at least 3 books within the next 12 months 
and may resign at any time thereafter, * Ironclad No-Risk 
Guarantee. If not satisfied with your books, return them 
within 10 days without obligation! • Exceptional Quality. 
All books are quality publishers' editions especially 
selected by our Editorial Board. (Publishers' Mens shown) 

All books are hardcover unless number is followed by a "P" for paperback. 
©1991 ELECTRONICS BOOK CLUB, Blue Ridge Summit, PA 17294-0810 



im Ei_ECTFm.cs Bqqk Cljb s 

Blue Ridge Summit, PA 17294-0810 



D YES! Please accept my membership in the Electronics Book Club and send (he 5 
volumes listed below, billing me $4.95- If not satisfied, I may return the books within 
ten days without obligation and have my membership cancelled. I agree to purchase 
at least 3 books at regular Club prices during the next 12 months and may resign any 
time thereafter. A shippingChandling charge and sales tax will be added to all orders. 



Name 



Address 
City 



State . 



. Zip. 



. Phone 



Signature ^ 

Valid for new members only. Foreign applicants will receive special ordering instructions. Canada must remit 
in U.S. currency. This order subject Id acceptance by tha Electronics Book Club. RE991 



03 

m 
-_ 

-i 
m 

<: 

ru 
m 

DO 



11 



ASK R-E 



Write to Ask R-E, Radio- Electronics, 500-B Bi-County Blvd., Farmingdale, NY 11735 



o 

z 
5 
pc 

t- 
o 

—i 

lU 

o 

5 
< 



SOFTWARE SOLUTION 

A few months back you an- 
swered a letter from a reader 
named T. Waller who wanted a 
keyboard indicator to show that a 
Print Screen operation was in 
progress. Although he asked for 
a hardware solution, I think a soft- 
ware solution is better. At first, it 
would seem as though putting an 
indicator on the screen during a 
print-screen operation would 
mess up the very display you 
were trying to print. Fortunately 
IBM uses two bytes for each 
screen location (one for the dis- 
played character and the other for 
the character's attribute) and only 
the first one is sent to the printer. I 
wrote a small program, PR_ 
IND.COM, that modifies the print- 
screen handler by adding code to 
the hardware interrupt set up by 
the ROM BIOS. When my program 
is run, it goes resident and makes 
the two bytes in the upper-right 
corner of the screen go inverse 
video whenever a Print-Screen 
operation is taking place. It works 
on both color and monochrome 
screens and takes only 416 bytes 
of memory from DOS. Hardware 
is okay for a lot of stuff but bit 
twiddling is better for others. — J. 
Sprung, San Pedro, CA. 

I couldn't agree with you more, and 
416 bytes is a cheap enough price to 
avoid having to screw around with 
hardware that's usually not only un- 
documented, but probably impossi- 
ble to deal with as well. In these days 
of ASIC's (application-specific IC's) 
and custom silicon, the amount of 
hardware diddling you can do is pretty 
limited anyway. 

I'm putting your source code and 
the COM file it produces on the RE- 
BBS (516-293-2283, 1200,2400. 
8N1) in a ZIP file called PR_IND.ZIP. 
Your program works well and is the 
kind of utility that, after you've used it 
a bit. you feel should have been a part 
of the computer in the first place. 
Congratulations on a nice piece of 
work. 

Any reader who wants to use the 
program (and that should be any 



reader with a DOS-based computer), 
can download the ZIP file from the 
bulletin board. For all those who don't 
have either a modem or the patience 
to deal with busy signals, the pro- 

LISTING 1 



JMP 01 5C 

PUSH DS 

PUSH AX 

CS: 

MOV DS, [0158] 

XOR BYTE PTR [809D],77 

XOR BYTE PTR [809F],77 

MOV AH, [009D] 

MOV AL, [009F] 

CS: 

MOV [015A],AX 

AND AX, 7777 

CMP AX, 7070 

JZ 0153 

MOV AX, 7070 

MOV [009D] ,AH 

MOV [009F],AL 

PUSHF 

CALL 0000:0000 

CS: 

MOV DS,[0158] 

XOR BYTE PTR [809D],77 

XOR BYTE PTR [809F],77 

CS: 

MOV AX, [015A] 

MOV [009D] ,AH 

MOV [009F] ,AL 

POP AX 

POP DS 

IRET 

MOV AX, 0707 

JMP 0129 

ADD [BX+SI+0707] ,DH 

MOV AX, 3505 

INT 21 

MOV [0132] ,BX 

MOV [0134] ,ES 

MOV DX,0102 

MOV AX, 2505 

INT 21 

MOV DX,015C 

INT 27 

RCX 

76 

N PS_IND.COM 

W 

Q 



gram can be created with any word 
processor that has the ability to save 
ASCII files. Type in the lines exactly 
as shown in Listing 1, end each line 
with a carriage return, and be sure to 
leave a blank line between the INT 27 
and RCX near the end of the listing. 
Save the listing in a file named "IN." 
When you've done that, you'll need 
a copy of the DEBUG program that 
came with DOS to turn the listing into 
a COM file. Put both the ASCII file 
you've called "IN" and DEBUG in the 
same directory and. at the DOS 
prompt, type "DEBUG " That will 

produce the program PR IND.COM 

that you can then run at the DOS 
prompt or make a permanent part of 
your AUTOEXEC.BAT file. 

If you get lots of error indications 
on the screen after you've run DE- 
BUG the most likely source of the 
problem is the file produced by your 
word processor. In order for DEBUG 
to take commands from a file (in this 
case, the "IN" file you just created), 
each line has to be followed by a car- 
riage return. When some word pro- 
cessors write an ASCII file, they 
include a line feed (OAh) along with 
each carriage return (ODh). If that's 
the way your word processor works, 
you'll have to use a different one to 
create the file. 

The program is too down and dirty 
to check whether it's already resi- 
dent, so make sure you don't load it 
more than once. Since it takes only 
416 byte of DOS memory, the best 
way to deal with it all is to automate 
everything by putting it in your AUTO- 
EXEC file and forgetting about the 
program entirely. 

Remember that the program will 
work only on the text screen. If you 
have some TSR that enables you to 
do a screen dump of a graphics 

screen, chances are PR IND won't 

give you an on screen indication that 
a Screen-Print operation is taking 
place. 

LED TROUBLES 
I'm currently working on a proj- 
ect that pulses some bright LED's 
at a frequency of 300 Hz while 
they're rotating to create a 



12 



&&* 




Five ways to look at 100 MHz. 
Starting at $2295! 



Just check the choices in our line-up of 
five 100 MHz oscilloscopes: 

• GPIB Programmability 

• Hardcopy Documentation 

• 100 MS/s Single-shot 

• Automatic Measurements 
Name your application, we'll provide 
the solution. 

Copyright (B 1991 Tcklrouii, Inc. All rights reserved. BOB- 137- 1 



Tek gives you the perfect blend of 
modem analog real-time and digital 
technologies in 100 MH? oscilloscopes. 
Whether it's hardcopy output from a 
fully programmable real-time scope, 
automatic measurements specified to 
.001%, or 100 MHz, 100 MS/s single- 
shot performance, no one has the 

CIRCLE 92 ON FREE INFORMATION CARD 



choices Tek does. To see it all, call 
your Tek rep or 1-800-426-2200. The 
closer you look, the more you'll 
appreciate Tek. 



I'/.M 



One company measures up. 

Tektronix 



m 



m 



13 



Safety, 

Security, 

Convenience, 

Entertainment 

and Energy 

Management 



Home Automation 

from Heath, 

the catalog 

that has it all... 

Enter the world of 

Home Automation, Remote 

lighting and appliance controls. 

Security alarms and lighting. 

Automated thermostats. 

Video monitoring systems. 

Whole-house security systems. 

They're all yours in the Heath 

Home Automation Catalog. To 

receive your FREE copy, 

call today toll-free. 

I-80O44-HEATH 

(1-800-444-3284) 



AumATO\i 

/ \ ft IEHH 



7!wBnpji ULm:M, 



gmm 



US* HI 



D 
< 



14 



Heath Company 

Marketing Dept. 020-090 
Benton Harbor, Ml 49022 



CIRCLE 86 ON FREE INFORMATION CARD 



stroboscopic effect. The circuit is 
battery powered, remote con- 
trolled, and uses CMOS 567 tone 
decoders to toggle a latching re- 
lay that connects the 300-Hz 
CMOS 555 oscillator and the 
LED's to power. Everything works 
fine until the LED's are con- 
nected. As soon as they light, it 
causes a voltage spike that 
makes the 567's trigger wildly. 
I've tried using voltage regulators 
and different sized filter capaci- 
tors at various points in the cir- 
cuit but haven't had any luck. The 
power source is limited to five 
AA's; is there an answer to this 
problem that won't cost more 
than a few milliamps? — D. Do- 
nofrio, Cleveland, OH 

The reason that you're having prob- 
lems with the circuit is that the 567's, 
and other phase-locked loops as well. 
all use internal voltage-controlled os- 
cillators CVCO's) to generate the sig- 
nals they need for frequency 
detection. Although they' re pretty im- 
mune to gradual shifts in the supply 
voltage, sudden swings usually 
cause them to lose lock and that 
plays havoc with their output states. 

The only way to keep that from 
happening is to regulate the voltage 
supply to the chips themselves. The 
standard solution would be to run 
them at a lower voltage. Since you'll 
always have at least six volts available 
from your five-battery supply, you 
might try one of the small. "L suffix 
regulators from National Semicon- 
ductor to provide a steady supply for 
the tone decoders. They're packaged 
in TO-92 type cases, use only a few 
milliamps. and can easily power the 
CMOS 567's. 

Since the key to making your cir- 
cuit work reliably is to isolate the tone 
decoders from the current demands 
of the LED's, you might be able to 
achieve that by using a resistor/ca- 
pacitor combination on each of the 
567 power inputs. As you can see in 
Fig. 1 , the resistor isolates the power 
input to the 567 from the main supply 
rail. You'll be able to use a fairly large 
resistor since the CMOS 567's run 
on flea power. An initial value of about 
150 ohms is a good starting point. 
The capacitor is there to provide an 
energy reserve when the LED's 
cause a voltage droop and a good 
starting value here would be some- 
where around 100 n.F. 

If all this fails and the voltage fluc- 



sv rxaAf 

&>/£. o — s^v 

/son. 



o — 



I 
I 



/SOI. A T£D 

OSV 

ro/Z S67' s 



C 

/ao/uf 
/6 V 

O 



FIG. 1— TO ISOLATE THE TONE decoders 
from the LED's you can use a resistor/ 
capacitor combination on each of the 567 
power inputs. The resistor isolates the 
power input to the 567 from the main sup- 
ply rail and the capacitor provides an en- 
ergy reserve when the LED's cause a 
voltage droop. 

tuations in the circuit still make the 
567's go nuts, you'll have no choice 
but to try the ultimate solution. It 
takes some circuit design and a few 
extra components, but there's no 
doubt it'll solve your problem. 

Since the reason you're having the 
problem in the first place is that 567's 
are turned on at the same time the 
LED's are being turned on, you can 
make the circuit work properly by 
making sure that the two things never 
happen together. The 567's should 
be off when the LED's are on and on 
only when the LED's are off. 

The idea of strobing power is a 
standard way of reducing the power 
requirements of a circuit. Basically it 
means you provide power only to the 
components you need. In your case, I 
would add circuitry that applies 
power only to the 567's when the 
output of the 555 oscillator is low. 
Since the rest state of your design 
shows that the 555 has a low output, 
the 567's would be constantly 
powered while the relay is open and 
intermittently powered on when the 
relay is closed (and the 555 is causing 
the LED's to light on and off). 

All you need to make that happen 
is a single transistor switch with the 
base controlled by the output of the 
555 and the power to the tone de- 
coders taken from the collector. 
Since the current requirements of the 
567 are so small, you can probably 
get by with one of the small-signal 
transistors like the 2N2222 or an 
equivalent PNP part. 

Either of the two methods (isolat- 
ing the 567 supply and strobing the 
power) may be the answer you're 
looking For. Try the resistor and ca- 
pacitor first and, if that doesn't do the 
trick, try adding the transistor and 
rewiring the circuit. R-E 



Afford. 
Ability 




In a dc power supply. 

Now, put a dependable, 30-watt dc 
power supply on your bench for 
just $300* You'll get the low 
noise your work demands (200 uV 
iTTts). Constant-voltage or constant- 
current operation. And built-in 
reliability ensured by conservative 
design margins and rigorous 
environmental testing. 

Outstanding value in a dc power 
supply. It's just one in a full line 
of basic Instruments developed 
by IIP to give you uncompro- 
mising performance at an 
affordable price. 

, To order, call HP DIRECT, 
1-800-538-8787, Ext.TW13. 

We'll ship your order the day it's 
received. Instruments come with a 
sixty-day, money-back guarantee. 
All you need is a HMi 

VISA 

company purchase Mi 
order or credit card. 



HP 30ivatt 
power supplies 


E3610A 


E3611A 


I 


Raege 1 


8V, 3A 


20V, 1.50A 


Range 2 


15V, 2A 


3SV, 0.BSA 


Load or line 
regulation 

Ripple end noise 
(10 HMO MHzl 


0.01% + 2mV 
200 ii V rmsG mVp-p 



There is a better way. 
mLrJk PACKARD 



C 1001 llfwtrtl.PwkaiiH-t>.TMNjr>lftVHE 



CIRCLE 189 ON FREE INFORMATION CARD 



CO 



m 



15 



LETTERS 



Write to Letters, Radio-Electronics, 500-B Bi-County Blvd., Farmingdale, NY 11735 



MULTILAYER SOLUTION 

I am an electronics technician in 
the Navy, currently working as an in- 
structor in the Navy's miniature/ 
micro-miniature (2M) electronic re- 
pair program. I read the letter from V. 
Deeoh. titled "Multilayer Woes." that 
appeared in the Ask R-E column in 
the June issue of Radio-Elec- 
tronics. The repair is possible. In 
fact, as I write this letter, I have five 
students in various stages of per- 
forming such a repair. It requires the 
use of various dental tools and a ster- 
eo-zoom microscope. It also requires 
a large amount of skill and patience. 
Of course, the damage would have to 
be isolated before the repair could be 
attempted, 

ET1CSW) BRIAN K. FOWLER 
Norfolk, VA 

ELECTRONIC COMPASS 
CORRECTIONS 

The "Electronic Compass" article 
(Radio-Electronics, June 1991) 
caught my attention, since I would 
like to build a device to measure mag- 
netic field strengths in the order of 
Earth's and less. I thought that i might 
even use part of the compass circuit- 
ry — until I discovered what looks like 
a fatal flaw. 

The article says that the Hall Effect 
sensors have a nominal 2.5-volt out- 
put that varies up or down about 1 .3 
mV per Gauss, depending on the 
field direction. Actually, that isn't 
stated clearly, but is implied and 
sounds reasonable. Thus, the inputs 
to resistors R1 and R2 will ideally be 
identical at 2.5 volts in the east-west 
orientation. By my concept of ideal 
op-amps, the voltage at pin 3 of IC2-a 
is entirely dependent upon the divider 
R4-R2, and the voltage from IC4 will 
be about 2.38 V. In an ideal op-amp, 
the voltage at pin 2 will be the same, 
g The only way that can happen with 
z both sensors at 2.5 volts is for pin 1 to 
§ be at zero volts, but the text says the 
o voltage will be between 2 and 3 volts 
ij and the rest of the circuit depends 
^ upon it being in that range. 
5 Next, I built that part of the circuit 
S using adjustable supplies to replace 



the sensors. As my theory predicted, 
the output at pin 1 is near zero (actu- 
ally 0.052 V) when equal voltages are 
applied to R1 and R2. 1 have found out 
from past tests of LM324's that they 
don't actually go to zero output. Mine 
are always 50 mV or so positive, and 
they are also quite nonlinear in gain in 
that region. I once attempted to use 
an LM324 as a differential amplifier 
with inputs quite similar to the com- 
pass circuit (differing by only milli- 
volts). I gave it up primarily because of 
the nonlinear gain with near zero out- 
put voltage. 

The text says that the gain of IC2-b 
is 100, but the resistors used with it 
give a gain of only 10. Also, the parts 
list is mixed up for the IC listing. 

Something is seriously wrong. My 
lab tests agree with my theory, yet 
the published circuit apparently 
works. Please explain, 
KENNETH E. STONE 
Cberryvale, KS 

Mr. Stone s analysis of circuit oper- 
ation is correct The circuit will oper- 
ate as published if the quiescent 
output voltage of IC4 is greater than 
that oflC3. That will cause pin 1 ofiC2 
to assume a positive value and oper- 
ate with linear circuit gain. 

In order to force the output of IC2 
pin 1 to assume a voltage level be- 
tween 2 and 3 volts, R4 should be 
deleted from the circuit. That will 
cause pins 3, 2. and 1 to assume a 
nominal voltage of 2.5 volts. The volt- 
age gain ofiC2-b is 10, as determined 
by the values of resistors R6and R5. 
The identification of the IC s specified 
in the parts list is incorrect IC2 is 
LM324N, while IC3 and IC4 are the 
Hall sensors. 
ANTHONY J. CARISTI 

PROFITS OR PROGRESS? 

Forty years ago, the first computer 
filled a large room, weighted 30 tons, 
and needed 19,000 vacuum tubes in 
order to function. Today a desktop 
computer with silicon chips instead of 
tubes can do anything the 20-ton di- 
nosaur did, and do it better. That's 
progress! 

If we had the same kind of progress 



in the automobile industry, today we 
would be driving around in all-electric 
cars powered by super batteries or 
capacitors that can be charged in 10 
minutes. Everything in the car would 
be controlled automatically by solid- 
state electronics. 

However, there is not enough profit 
in trouble-free, non-polluting electric 
cars. The manufacturers prefer to 
give us the same old box on wheels 
that Grandpa drove, with the same 
old gasoline engine that needs oil 
changes and antifreeze, tuneups and 
lots of repairs. The more complicated 
they can make the car, the more 
money they make. 

It's time for something better. Tell 
your congressman to outlaw the air- 
polluting, oil-dependent, gasoline- 
powered automobile, so the man- 
ufacturers will be forced to give us 
clean, modern electric cars. The 
sooner the better, 
TOM ANDERSON 
The Electric Automobile Clubs of 
America 
Valley Forge, PA 

HIGH-END HOOPLA 

I've followed with interest the con- 
troversy that Larry Klein initiated in 
Audio Update, in the December 1990 
issue of Radio-Electronics with 
his piece on "transfer functions." 
After reading John Atkinson's nega- 
tive response to Klein's points in the 
March Letters column, I decided to 
read an issue of Stereophile to get a 
better handle on the fuss. After so 
doing, I think that magazine would be 
better titled (to borrow a phrase from 
Hunter Thompson) Fear and Loathing 
on the High-End Trail. A partial list of 
the things their staff doesn't like in- 
cludes the following items: The Audio 
Engineering Society, Stereo Review. 
audio frequency modulation video re- 
corders, CD players, and the Voice of 
Reason. 

If there is one key issue that sepa- 
rates high-end aficionados from more 
sensible audiophiles, it is the impor- 
tance of frequency response. Aside 
from such factors as amplifier power 
and speaker power- hand ling capacity, 



16 



which determine how loud a system 
will piay. much research has shown 
that frequency response alone deter- 
mines the sonic character of any 
given component. In 1978, Mark 
Davis and his colleagues at M.I.T. re- 
duced speaker differences to just 
two factors: frequency response and 
radiation pattern (High Fidelity, 
March 1980). All the while, high-end 
advocates skirted the matter of fre- 
quency response, emphasizing in- 
stead an endless panorama of 
strange, often unmeasurable, aura 
and electrical minutiae. (In addition, 
since speakers have the highest lin- 
ear distortion of any component in 
the chain and since they determine 
the sound-radiation pattern, they 
have a much greater effect on a sys- 
tem's overall sonic quality than any 
other single component — another 
fact that high-end proponents seem 
to anxiously deny!) 

I personally find it difficult to buy 
new and expensive components with 
the hope of obtaining more accurate 
sound reproduction because I know 
from experience that I'll be able to 
equalize the old equipment to sound 
so much like the new that any residual 
differences, usually in the bass re- 
gion, won't justify the expense. 
TOM GORDON 
Berkeley, CA 

USING THE MAGNETIC 
FIELD METER 

I was happy to see the "Magnetic 
Field Meter" project in the April issue 
of Radio- Electronics. The meter 
allows a quick (and inexpensive) as- 
sessment of home and business 
magnetic-field conditions for those of 
us who are unwilling to wait for U.S. 
standards to be established. I have 
some additional suggestions regard- 
ing the calibration use of such a coil- 
based meter. 

For both calibration and use. the 
orientation of the coil is critical. The 
single-coil design is sensitive only to 
fields in one of three axes. The "right- 
hand rule" gives the relationship be- 
tween the direction of field-producing 
current flow and the orientation of the 
coil axis for maximum sensitivity. For 
the calibration technique shown in 
Fig. 6 of the article, the meter pick-up 
coil should be at right angles to the 
current flow, hence parallel to the axis 
of the transmitting coil. 

When conducting a survey, the 
meter coil axis should be oriented 



No Better Probe Ever at this Price! 




Shown here 

Model SP 150 Switchable lx-IOx .... 



Risetime less than 1.5 nsec. 



Free prohc guide shows economies] 
rbptftcemcttU farTeklrnrtix. II-?. 

Philip* imd nil others 



• Universal 

Works with all oscilloscopes 

• Rugged 

Flexible cable lasts longer- 
Replaceable ground lead 



Economical 

Substantial savings compared to 

OEM probes 

10 Day Return Policy 

Guaranteed performance and quality 



PROBES, INC. 



TH 



9178 Brown Deer Road, San Diego. CA 92121 
Toll Free 1-800-368-5719 



CIRCLE 123 ON FREE INFORMATION CARD 



along each of three perpendicular 
axes and the strongest reading used 
for analysis. The external coil option 
would make that easier. The field 
strength due to monitors and due to 
unbalanced wiring usually has a 
strong maximum in one direction. The 
more expensive, professional meters 
typically use three perpendicular 
coils (or three Hall-effect devices) 
and electronically develop the true 
maximum field. 

I would also like to provide some 
reference points of EMF field 
strengths to augment the values 
given in the article. The typical unbal- 
anced current flow in the center-tap 
ground of a 240-volt drop to a house 
is 0-4 amps at 60 Hz. That corre- 
sponds to a magnetic field of 0-2 u.T 
(0-20 milliGauss) at 1 inch from the 
current. The current usually flows 
down the outside wall of the house 
and through the cold water pipe along 
the basement ceiling. The quickest 
solution to such fields is to move fur- 
niture such as beds and cribs away 
from the area so that exposure time is 
reduced. The current could also be 
rerouted by an electrician with suit- 
able copper ground strapping. 



The new Swedish EMF guidelines 
for computer monitors (VDT's) are: 

• 50 cm (20 in.), 5 Hz-2 kHz: 0.25 
pT (2.5 mG) 

• 50 cm (20 in.), 2 kHz-400kHz: 
0.025 m-T (0.25 mG) 

Source: VDTNews, Nov./Dec, 1990 
Several manufacturers are now 
making low-radiation color monitors 
for the U.S. market, including all 
IBM's made since September 19S9 
and the new NEC 3Ds model. Many 
monitors exhibit low fields already, 
and can be tested with the 
Gaussmeter before purchase, 
WILLIAM SNYDER 
Rochester, NY 

NOBODY'S FOOL 

I just finished reading the article on 
making a laser printer out of a monitor 
and a copier (Radio-Electronics, 
April 1991). It's a good idea in theory, 
but in practice you could have a prob- 
lem. Some copiers will not run with w 
the lamp removed. If you have that IS 
problem, you are going to have to m 
create a path for the lamp voltage to |g 
"fool" the circuit. 53 

RICK SCHWILL - 

Phoenix, AZ R-E 5 



17 




nnESMnEnsE 




R.L. Drake R-8 World Band Shortwave Receiver 



In our younger days, we never had 
the means to get the shortwave 
equipment that we really wanted. 
Our ham shack and shortwave 
monitoring setup were functional, 
and we did reasonably well, consider- 
ing our non-existent budget. But 
every visit to a swap meet made our 
mouths water. And every magazine 
had advertisements of glorious 
equipment that we wanted. We knew 
that one day, we would own a commu- 
nications receiver from R.L. Drake 
(P.O. Box 112, Miamisburg, OH 
45342). 

We never got a chance, though. In 
the early 1980's, Drake dropped 
communications receivers to pursue 
the satellite-TV business, where 
they've done quite well. But now 
they're back in business with the R8, 
a world band shortwave receiver re- 
engineered from the ground up. 

They couldn't have picked a better 
time. Shortwave radio was undergo- 
ing healthy growth in the U.S. even 
before such dramatic events as the 
reunification of Germany, the revolu- 
tion in Romania, and the Persian Gulf 
war. Even with the instant access to 
news that we can get through CNN 
and local all-news stations, people 
are tuning in to shortwave for some- 
thing that is sometimes more difficult 
to find: a diversity of opinion. Al- 
though broadcast schedules and ad- 
vanced taping of shows means that 
the news that you hear on the short- 
wave bands is often a few hours old, 
your chances of hearing a fresh per- 
spective are still pretty good. And the 
chance of hearing stories not even 
covered in our news-saturated media 
is even better. 

The R8 offers continuous frequen- 
cy coverage from 100 kHz to 30 MHz, 
which takes in the thirteen world-ra- 
dio bands and everything in between. 
The table-top receiver measures 
roughly 13x5x13 inches, and 
weighs about 13 pounds. Although 
it's not designed for a mobile environ- 
ment, the R8 does offer a fused 12- 
volt DC input connector so that you 
can power the receiver, for example, 
from the cigarette lighter in your car. 




R.L Drake 
is back with a 
vengence! 



CIRCLE 10 ON FREE INFORMATION CARD 



The AC input gives you plenty of op- 
tions for world-wide operations: 100-, 
120-, 200- , and 240-volt operation 
are supported at 50 or 60 Hz. 

The front panel is dominated by a 
large, backlit liquid crystal display. We 
found it to be difficult to read at sharp- 
er angles. Head on, however, it's a 
delight. The seven-digit display pro- 
vides a tuning resolution of 10 Hz. 

The front panel isn't as cluttered 
with controls as many of its com- 
petitors. That doesn't mean, how- 
ever, that the R8 is short on 
features — features that really mean 
something when you're trying to cap- 
ture the weak signals in crowded 
bands. Five receive bandwidths (6, 4, 
2.3, 1.8 and 0.5 kHz) are provided. 
When you select one of the receiver's 
six modes CAM. FM, CW. RTTY. LSB. 
and USB) the R8 automatically se- 
lects an appropriate bandwidth C1.8 
kHz for RTTY, for example), but you 
are free to select another with the 
touch of a button. For example, if in- 
terference makes it difficult to intel- 
ligibly receive AM broadcasts using 
the 6-kHz bandwidth, you can reduce 
the setting to cut interference. 

Synchronous detector 

One of the inherent "problems" 
with shortwave reception — re- 
gardless of the receiver — is signal 
fading due to propagation distur- 
bances. To combat fading, the R8 
offers a switchable (slow, fast, or off) 
AGC or automatic gain control. In 
most cases, the AGC does a good 



job of keeping the signal listenable. 
But even with AGC, fading can cause 
distortion. That's where the R8's syn- 
chronous detector comes in. A re- 
ceiver-generated local oscillator, syn- 
chronized in frequency and phase to 
the carrier, is used in demodulating 
the signal. World-band listeners will 
really appreciate how it can enhance 
fidelity by reducing distortion. 

A passband offset control is an- 
other reception-enhancing feature 
that deserves mention, it allows you 
to electronically shift the receiver's IF 
frequency without disturbing the op- 
erating frequency! Thus, in many 
cases, you are able to move interfer- 
ing signals out of the passband. 

The synchronous detector and 
passband-offset capability — along 
with a tunable notch filter, dual-mode 
noise blanker, RF preamplifier for 
boosting signals over 5 MHz, and 
tone control — all help to dig the tough 
signals out of the crowded bands. In 
fact, there's not much more you could 
ask for. But the R8 doesn't just offer 
superb reception capability. It also of- 
fers a host of other features. 

One hundred memories store not 
only the frequency of a station, but 
also the complete receiver setup. 
Since the memory is stored in 
EEPROM, there's no need for battery 
backup. Tuning can be done by direct- 
frequency entry, tuning the large tun- 
ing dial (the faster you turn the dial, 
the faster the frequency shifts), or up 
and down keys that provide for larger 
continued on page 82 



18 



5 sure steps to a fast start 
as a high-paid 

computer service technician 



1 



Choose training 
that's right for today's 
good jobs 




1992 Good pay, too! 2002 



Jobs for computer service technicians 
will almost double in the next 10 years, 
according to the latest Department of 
Labor projections. For you, that means 
unlimited opportunities for advance- 
ment, a new career, or even a com- 
puter service business of your own. 

But to succeed in computer service today, you need training — 
complete, practical training that gives you the confidence to service any 
brand of computer. You need NRI training. 

Only NRI— the leader in career-building, at-home electronics training 
for more than 75 years — gives you practical knowledge, hands-on skill, 
and real-world experience with a powerful 386sx/20 MHz computer you 
keep. Only NRI gives you everything you need for a fast start as a high- 
paid computer service technician. 




2 



ia Go beyond 
"book learning" 
to get true hands- 
on experience 

NRI knows you learn better by 
doing. So NRI training works 
overtime to give you that 
invaluable practical experience. 
You first read about the subject, 
studying diagrams, schematics, and photos that make the subject even 
clearer. Then you do. You build, examine, remove, test, repair, replace. 
You discover for yourself the feel of the real thing, the confidence gained 
only with experience. 



k A 



3 



i NEW! 
386sx/20 MHz 

Mini Tower 
f Computer! 



Get inside 
a powerful com- 
puter system 

If you really want to get ahead 
in computer service, you have 
to get inside a state-of-the-art 
computer system. That's why 
NRI now includes the powerful 
new West Coast 386sx/20 MHz 
mini tower computer as the 
centerpiece of your hands-on 
training. 

As you build this 1 meg 
RAM, 32-bit CPU computer 
from the keyboard up, you 
actually see lor yourself 
how each section of your 
computer works. You 

assemble and test your computer's "intelligent" keyboard, install the 
power supply and high-density floppy disk drive, then interface the high- 
resolution monitor. But that's not all 

You go on to install a powerful new 40 meg IDE hard disk drive — 
today's most-wanted computer peripheral— included in your course to 
dramatically increase the data storage capacity of your computer while 
giving you lightning-quick data access. 



Plus, now you train with and keep the latest in diag 
nostic hardware and software: the R.A.C.E.R. plug-in 
diagnostic card and QuickTech diagnostic software, 
both from Ultra-X. Using these state-of-the-art diag- 
nostic tools, you learn to quickly identify and ser- 
vice virtually any 
computer problem 
on IBM-compat- 
ible machines. 



4. 





f ■ Make sure you've always got 
someone to turn to for help 

Throughout your NRI 
training, you've got the 
full support of your 
personal NRI instructor 
and the entire NRI 
technical staff. Always 
ready to answer your 
questions and help you if 
you should hit a snag, 
your instructors will 
make you feel as if 
you're in a classroom of 
one, giving you as much time and personal attention as you need. 




5, 



Step into a bright new future in 
computer service— start by sending for 
your FREE catalog today! 




Discover for yourself how easy NRI makes it to 
succeed in computer service. Send today for NRJ's 
big, full-color catalog describing every aspect of 
NRI's one-of-a-kind computer training, as well as 
training in TV/video/audio servicing, telecom- 
munications, industrial electronics, and other 
growing high-tech career fields. 

If the coupon is missing, write to: NRI 
School of Electronics, McGraw-Hill Continuing 
Education Center, 4401 Connecticut Avenue. NW, 
Washington, DC 20008. 

R.A.C.E.R. and QuickTech are registered trademarks ol Ullra-X, INC, 




School of 
Electronics 



i:nii 



McGraw-Hill Continuing Education Center 

4401 Connecticut Avenue, NW, Washington, DC 20008 

[VfcHECK ONE CATALOG ONLY 
U Microcomputer Servicing 

□ TV/Video/Audio Servicing 
D Telecommunications 

□ Industrial Electronics/ Robotics 

□ Basic Electronics 



For career courses 

approved under Gl Bill 

[J check for details. 



D Computer Programming 
D PC Software Engineering Using C 
U Desktop Publishing & Design 
□ Word Processing Home Business 
O Bookkeeping & Accounting 



Name . 



Address 



City 



State . 



.Zip. 



Accredited Member, National Home Study Council 



CO 

m 

-o 



CD 

m 

J3 

to 
to 



21 



09 

g 

z 
o 

cr 
P 

o 

LU 





Q 
< 
■T 



PCX! BUS-EXPANSION 
CHASSIS. PCXI is a mod- 
ular, industrial PC, based 
on a 13-slot passive back- 
plane. Rapid Systems' 
PX159I bus-expansion 
chassis includes a 13-slot 
ISA (industry standard ar- 
chitecture) standard back- 
plane with a 200-watt 
modular power supply, a 
single-slot module, one 
hare expansion card, and 
front-end cabling needed 
to extend from the PCXI 
expansion chassis to any 
laptop or desktop PC. 
Using a standard PC with 
the PX1591, the PCXI chas- 
sis provides the benefits of 
FMI/RFI shielding, protec- 
tion against vibration, and 
specified industrial cooling 
through a metal-shielded 




CIRCLE 16 ON FREE INFORMATION CARD 



module cover with top and 
bottom cooling slots. Ap- 
plications include field ser- 
vice, ATE development, 
factory automation, and in- 
dustrial testing. 
The PXI59I bus-expan- 



sion chassis costs 
$2395 —Rapid Sys- 
tems, Inc., 433 North 
34th Street, Seattle. WA 
98103; 

Phone:206-548-0322; Fax: 
206-547-8311. 



AMATEUR-TV FILTER. 

Designed for use in ama- 
teur televisions, the FL-407 
Vestigial Sideband Filter 
from International Crystal 
Mfg Co. is available in fre- 
quencies between 420 and 
440 MHz. The 6-MHz nom- 
inal bandwidth and low-loss 
design are intended for 
transmitter or receiver use. 
Two filters can be used for 
repeater operation. The 
seven-pole, interdigital de- 
sign provides excellent 
sideband suppression and 
filtering when used alone, 
or in pairs. Heavy-duty con- 
struction ensures stable 
operation and long life. The 
FL-4 07 measures 



s! 



CIRCLE 17 ON FREE 
INFORMATION CARD 



2Vax8 ,3 /i 6 x20 5 /8 inches. 
N-type connectors are 
standard. 

The FL-407 vestigial 
sideband filter costs 
$249. — International 
Crystal Manufactur- 
ing Company, Inc., P.O. 
Box 26330, 701 West 
Sheridan, Oklahoma City, 
OK 73126-0330; Phone: 
800-426-9825 or 
405-236-3741; Fax: 
405-235-1904. 

FIELD-SERVICE DMM. 

Aimed specifically at field- 
service technicians, the 
HB70 Series digital multi- 
meters from Fieldpiece In- 
struments look and func- 
tion differently from others 
on the market. Two profes- 
sional-grade, heavy-duty 
meters, which provide only 
those functions needed 
most by service techni- 
cians, feature a single 
easy-to-use rotary switch 



for function and range se- 
lection. Models HB71 and 
HB73 each have 24 ranges 
in AC and DC volts, AC and 
DC amps, and ohms. The 
model HB73 (pictured) 
adds six capacitance 




CIRCLE 18 ON FREE 
INFORMATION CARD 



ranges up to 200 |*F, All 
voltage ranges withstand 
1500VDC and 1000VAC; 
other ranges withstand 
500 volts AC or DC. The 
manual-ranging meters in- 
clude a dangerous-voltage 
warning indicator that 
causes an LCD icon to 
flash intermittently and a 
beeper to be activated 
when a voltage over 28V 
AC or DC is encountered. 
All of each meter's ca- 
pabilities are displayed on 
the front of the instrument; 
the one dial is used to 
choose from the "menu" 
on the meter's face. The 
rugged design is shatter-re- 
sistant and features O-ring 
seals to protect against 
contaminants, full 600-volt 
fusing on all current jacks, 
and MOV's to protect 
against transients. 

The models HB71 and 
HB73 digital multimeters 
have suggested list prices 
of $99 and $109, respec- 
tively. — Fieldpiece In- 
struments, Inc.. 832 2 B 
Artesia Blvd., Buena Park, 
CA 90621; Phone: 
714-992-1239; Fax: 
714-992-1239. 

SOLDERING IRON 
SPONGE. The Swiss 
Sponge (named for the 
cheese, not the country) 
features multiple holes for 
improved tip cleaning. The 
holes trap the solder balls 
and drop them to the bot- 
tom of the sponge tray 
where they belong. Virtual 
Industries' Swiss Sponge 
is available in a variety of 
sizes to fit most makes of 
soldering-iron sponge 
trays, A "one-size-fits-all" 
sponge measures 
3.5x4.8 inches and fea- 
tures patterns matching 
popular tray sizes so that 



22 





SM 




(1 ) Hobby Motor, For robotics and 
projects. IV2 to 3VDC. About 1*" 
long. #273-223 99C 

(2) High-Speed 12VDC Motor. 
Up to 15,200 RPM. About 2" long 
(with shaft). #273-255 2.99 



Parts Special-Order Hotline. Your local Radio Shack offers a 
huge selection of electronic components. Plus, we can special- 
order 10,000 additional items from our main warehouse — ICs, 
tubes, semiconductors, crystals, phono cartridges and styli, 
even SAMS* manuals. Service is fast and there is no postage 
charge, no minimum order. 

Talking Multimeter, Timesaving speecn output! Take readings 
without having to glance over at the meter. Press a button on the 
probe and this meter calls out the reading in clear English while 
displaying it. Features full autoranging, autopolarity, liquid crys- 
tal display with taw- battery and over -range indicators, continuity 
beeper, diode-check mode and 10-megohm input. With leads. 
#22-164 99.95 



m 



m 



« 



. = m»= 



(1) 4- in -1 Solder! ng Tool . No cords or cylinde rs ! Precision so I de ri ng w herever 
you need it. Operates anywhere on standard butane lighter fuel. Up to 60 
minutes use per lank. Easy to use — refills in just seconds. #64-2161 . . 31.95 
Optional Conversion Tips. Available from CMC Special Order "Hotline". 

(2) Blow Torch. Keeps a steady flame. #64-2169 9.95 

(3) Hot Knife. Ideal tor design and repair. #64-2170 9.95 

(4) Heat Blower. Puts the heat on for quick drying #64-2169 9,95 




o 



(1) 



MX 



(2) 



W 



O) 



(1) Mini Piezo Speaker. Only 
1 3, h2"- diameter. Use with IC driv- 
ers. #273-091 2.49 

{2) "Ding-Dong" Chime. Re- 
quires 6 to 18VDC. #273-071, 8,99 
(3) Mini Buzzer. Loud, yet only 7 
mA at 12VDC, #273-074 . . , 2.99 



E 



■— — ■ 



SENSOR 



NEW! TV/VCR Remote Control 
Tester. Senses infrared light from 
remotes to tell you if they are work- 
ing. Al so I ocales n ear- i n 1 rared rad i- 
ation emanating from either LED or 
laser sources. Pocket size. 
#276-0099 5.95 



^hmW 



in 



(3) r W 

< 2 ) (4) (SJ 



XLR Audio Connectors 



'"■:! 


Type 


Cat. No. 


Each 


2 


Three-Pin Plug 
Inline Socket 


274-010 

274-011 


2.99 
2.99 


3 

■•■ 
5 


Panel Socket 
XLR Plug Adapter 

1 /*"-Plug Adapter 


274-013 
274-016 

274- 017 


3.69 
11.99 
11.99 




Project Battery Holders. 

(1) 2 "AAA". #270-398 79* 

(2) 4 "D". #270-389 1.59 

(3) 1 "N". #270-405 59« 

(4) 2 "C". #270-385 1.29 



Portable Shortwave Antenna. 

Pulls in the DX! Great for traveling. 
Clips over telescoping rod an- 
tenna. Wire extends up to 23 ft. 
Dramatically improves reception 
on worldband portables. 
#278-1374 8.95 




NEW! 25-Pin Female D-Sub Con- 
nector. Right-angle mounting, de- 
signed for Experimenter PC/XT 
Card-Edge Compatible Plug-In 
Card (at right) to provide standard 
25 -pin in put /output port. 
#276-1504 2.39 




NEWI Archer 1 Experimenter's Plug-In Card. PC/XT compatible prototype 
card for bread boarding digital /analog circuits. Plated through holes, power 
and ground bus grids, 8-bit 31/62 plated-edge contacts, I/O mounting area 
for 25-pin d-sub connector (at left). #276-1598 29.95 



ID 



(2) 



IHI 



m 






(1) Hi-Precision 10K-ohm Ther- 
mistor. #271-110 1.99 

(2) 200 Surface-Mount Resis- 
tors. 5% to I. #271-313, Set 4.99 

(3) Pocket Color Guide. Finds re- 
sistor, capacitor, Inductor values, 
#271-1210 79« 



Since 1921 Radio Shack has been the place to obtain up-to-date 
electronic parts as well as quality tools, test equipment and accessories 
at low prices. 7000 locations to serve you — NOBODY COMPARES 



Prices apply at participating Radio Snack stores and dealers. Radio Shack is a division ol Tandy Corporation 

CIRCLE 78 ON FFiEE INFORMATION CARD 



.Radio /hack 

America's technology store 



m 

I 

CD 

m 
2J 



23 




CIRCLE 19 ON FREE 
INFORMATION CARD 

the user can cut it to fit 
using scissors. 

Suggested list prices for 
the Swiss Sponge range 
from $.75 to $1 .50 each. — 
Virtual Industries, Inc., 20 
Mountview Lane, Unit E, 
Colorado Springs, CO 
80907; Phone: 

719-598-1369; Fax: 
719-594-0147. 

SOLDERLESS BREAD- 
BOARDS. Designed for 
use by students, hob- 
byists, and circuit-design 
engineers, the X-tra Edge 
solderless breadboards 
from Chenesko Products 



feature an extra multi-use 
edge panel for organizing 
and mounting components 
that do not fit into the nor- 
mal DIP spacing of sol- 
derless breadboard socket 
connections. Available in 
four sizes, each contains a 
solderless breadboard 
area that contains both dis- 
tribution and terminal strips 
to accommodate all DIP 
sizes, lead components 
CO. 3-0. 8mm lead diame- 
ter), and wire gauge of 
AWG 20-29 for intercon- 
necting components. The 
breadboard contacts, 
spaced at 0.1 -inch on cen- 




CIRCLE 20 ON FREE 
INFORMATION CARD 



ter, are made of phosphor 
bronze nickel- plated for re- 
liable low-resistance con- 
tacts. Initial contact resis- 
tance is less than 3 
milliohms at 1 kHz C20 C C) 
and the contacts are rated 
for a minimum of 10,000 in- 
out insertions. For easy 
connecting of external 
power supplies, four multi- 
purpose binding posts that 
accept both standard ba- 
nana jacks and lead wires 
are standard on each 
model. The removable 
edge panel features a vari- 
ety of geometric cutouts 
that allow the panel to hold 
transistors, stud rectifiers, 
triacs, SCR s. DIAC's, volt- 
age regulators, heat sinks, 
rheostats, switches, buzz- 
ers, and fuse holders in a 
variety of package sizes. 

Models NB-112P 
(4.3X7.4 inches, 810 tie- 
points, 61 rows for DIP's), 
NB-124P(6.5x 7.4 inches, 
1620 tie-points, 122 rows 
for DIP's), NB-134P 



(7,9 x 7.4 inches, 2230 tie- 
points. 1 83 rows for DIP's). 
and NB-I45P (9.7x7.4 
inches, 2940 tie-points, 
244 rows for DIP's) cost 
$7.50, $16, $21, and $27, 
respectively. — Che- 
nesko Products, Inc., 
62 North Coleman Road, 
Centereach, NY 11720; 
Phone: 800-221-3516 or 
516-736-7977; Fax; 
516-732-4650. 

ELF METER. To measure 
the strength of potentially 
harmful magnetic fields 
generated by AC electrical 
devices, F.W. Bell has intro- 
duced the model 4060 ELF 
(extremely low frequency) 
meter. Electromagnetic 
field (EMF) radiation, which 
is produced by power- 
transmission lines, com- 
puters, microwaves, and 
other electrical appliances, 
is under investigation by 
both private and govern- 
mental agencies for its 
possible link to cancer, leu- 



o 

Q 
< 

£ 
24 



CABLE - TV 



TUNABLE 

NOTCH FILTERS 

• FOR ELIMINATION OF SEVERE INTERFERENCE 

• FOR "CENSORING" OF ADULT BROADCASTS 

• 45dB 

AT CENTER FREQUENCY 

• ■5-effl 

AT 2 MHZ FROM CENTER 

• 2dB 

INSERTION LOSS 





MODEL 


TUNES TO CHANNEL 


PRICE 


SHIPPING 


23H 


2 OR 3 (or 6 meter tern) 


$30 


NO 
SHIPPING 

OR 

C.O.D. 

CHARGES 


46FM 


4, 5, OR 6 (or any FM station) 


$30 


713 


7,8,9, 10, 11, 12, OR 13 


£30 


1417 


14(A). 15(B), 16(C), OR 17(D) 


$30 


1622 


18(E). 19(F), 20(G). 21(H). OR 22(1} 


$30 


3 for $75-10 for $200 - Mix or Match 

30 DAY MONEY BACK GUARANTEE (3 FILTER LIMIT) 


FAST DELIVERY 

CALL TOLL FREE FOR C.O.D. OR SEND CHECK TO ORDER 



STAR CIRCUITS 

P.O. BOX 94917 
LAS VEGAS, NV 89193 



Call (800) 992-9943 

Over 35,000 
Electronic Components 

Call Today for Your 
FREE SUBSCRIPTION 

if You Order Today, 




Try the 

M-lEctfvmcs 

bulletin board 
system 

(RE-BBS) 
516-293-2283 



The more you use it the 
more useful it becomes. 

Wo support 1200 and 2400 
baud operation. 

Parameters: 8N1 (8 data 
bits, no parity, 1 stop bit) 
or 7E1 (7 data bits, even 
parity, 1 stop bit). 

Add yourself to our user 
files tu Increase your 
access. 

Communicate with other 
R-E readers. 

Leave your comments on 
R-E with the SYS0P 



RE-BBS 
516-293-2283 



CIRCLE 117 ON FREE INFORMATION CARD 



kemia, and birth defects. 
The ELF meter can help the 
user to determine ex- 
posure levels. The com- 




CIRCLE 21 ON FREE 
INFORMATION CARD 

pact device features a 3'/2- 
digit LCD readout that indi- 
cates field strength in ei- 
ther milliGauss or Gauss 
(depending on the setting). 
A single control acts as 
both an on-off and a high/ 
low range switch. Readings 
are taken simply by holding 
the meter near the source 
to be measured. The ELF 
meter has an accuracy of 
± 1 % and a resolution of 1 
mG or 10 mG. 

The 4060 ELF meter has 
a suggested list price of 
$179— F.W. Bell, Inc., 
6120 Hanging Moss Road, 
Orlando, FL; Phone: 
407-678-7308. 

MINIATURE MICRO- 
CONTROLLER. Called 
the Flip Stik because it 
functions as an expandable 
microprocessor when 
plugged in one way and a 
single-board micro- 
controller when plugged in 
the other way. Dallas Semi- 
conductor's DS2340 ac- 
cepts software updates via 
its serial port while it is in 
the system, with no com- 
ponent removal required. 
The Flip Stik is roughly the 
size of a piece of chewing 
gum, and consumes very 
little power. It supports 
DOS-equivalent operating 
systems for diskless em- 
bedded systems, allowing 
application developments 



using standard DOS func- 
tion calls. Thanks to its in- 
system reconfigurability. an 
embedded system that in- 
corporates the Flip Stik 
can be configured with 
customized software just 
before shipping without 
opening its enclosure. 
Software upgrades can 
even be downloaded over 
the telephone line from a 
remote PC. 

The Flip Stik incorpo- 
rates a V40 micro- 
processor (software-com- 
patible with the 8088), up 
to 256K bytes of non- 
volatile RAM, and a 
DS5340 "Softener" chip. 
That chip "crash-proofs" 
the microprocessor to 
safeguard data against 
power failure. Because the 
V40 executes the native in- 
struction set of the PC, 
programmers can use the 




CIRCLE 22 ON FREE 
INFORMATION CARD 

software base with which 
they are already familiar: 
they don't have to learn a 
new language or buy spe- 
cial development systems. 
They can write software for 
the Flip Stik on their desk- 
top PC's and later port it to 
the embedded system. 
The V40 also provides a 
serial port, interrupt con- 
troller, timer-counters, and 
a DMA controller. The soft- 
ener chip complements 
those functions with a 
clock oscillator, power 
monitor, watchdog timer, 
programmable address de- 
coder, dual-port register 
file, and parallel I/O ports. 
The DS2340 Flip Stik 
costs $54.30 in quantities 
of 1000— Dallas Semi- 
conductor, 4401 South 
Beitwood Parkway, Dallas, 
TX 75244: Phone: 
214-450-0448. R-E 



Earn Your B.S. Degree 

in 

ELECTRONICS 

or 
COMPUTERS 




By Studying at Home 

Grantham College of Engineering, 
now in our 4 1st year, is highly ex- 
perienced in "distance education" — 
teaching by correspondence — through 
printed materials, computer materials, 
fax, and phone. 

No commuting to class. Study at 
your own pace, while continuing on 
your present job. Learn from easy-to- 
understand but complete and thorough 
lesson materials, with additional help 
from our instructors. 

Our Computer B.S. Degree Pro- 
gram includes courses in BASIC, 
PASCAL and C languages — as well as 
Assembly Language, MS DOS, CADD, 
Robotics, and much more. 

Our Electronics B.S. Degree Pro- 
gram includes courses in Solid-State 
Circuit Analysis and Design, Control 
Systems, Analog/ Digital Communica- 
tions, Microwave Engr, and much more. 

An important part of being pre- 
pared to move up is holding the right 
college degree, and the absolutely neces- 
sary part is knowing your field. 
Grantham can help you both ways — 
to learn more and to earn your degree 
in the process. 

Write or phone for our free 
catalog. Toll free, 1-800-955-2527, or 
see mailing address below. 



Accredited by 

the Accrediting Commission of the 

National Home Study Council 



GRANTHAM 

College of Engineering 

Grantham College Road 
Slidell, LA 70460 



C/3 

m 
m 

CD 

m 

3J 

CO 

<o 



25 



NEW LIT 



Use The Free Information Card for fast response. 



TONER CARTRIDGE 
RECHARGE CATALOG; 
from Chenesko Prod- 
ucts Inc., 62 North Col- 
e m a n Road, Cen- 
tereach, NY 11720; 
Phone: 800-221-3516 or 
516-736-7977; Fax: 
516-732-4650; free. 

Anyone who owns a 
laser printer knows how 
costly replacement toner 



Toner 
Cartridge Recharge 

Kits « &upg]it& • Sirica 




,-'><- tosiosr 

. .-■ -Z& 

Kx^ZL ■ T 

CIRCLE 337 ON FREE 
INFORMATION CARD 

cartridges can be. This cat- 
alog explains alternatives 
to new cartridges, describ- 
ing recharged cartridges — 
in do-it-yourself or full-ser- 
vice forms — that can be 
used with the HP LaserJet. 
LaserJet Plus, and Laser- 
Jet Series II, IID. IIP and III: 
Apple LaserWriter, Laser- 
Writer Plus, and Laser- 
Writer IINT/IINTX; and 
many other models. When 
handled properly, the car- 
tridges can be cleaned out, 
modified, and then re- 
charged with new toner 
several times before the 
photoconductive drum in 
the toner cartridge wears 
out. This catalog describes 
three methods of recharge. 
_ For the handyman, six dif- 
8> ferent kits are available with 
e complete instructions on 
m how to modify and re- 
§ charge toner cartridges, 
t For the person who wants 
ot to start a recharge busi- 



ness, a complete selection 
of toner-recharge products 
are offered at bulk prices. 
Those include generic 
toner, graphic toner, spe- 
cial replacement felt, new 
fixing rods, sealing strips, 
plugs labels, tools, clean 
air, wipes, and vacuums. 
Detailed assembly instruc- 
tions are free with pur- 
chase. For those who lack 
the time or inclination to do 
the job themselves, the 
catalog also details Che- 
nesko's mail-in service. 
The first time it is sent in, 
the cartridge is cleaned, 
modified, and recharged. 
The modification allows it 
to be easily refilled by the 
customer the second time, 
by purchasing the replace- 
ment toner and felt pad. 

HOW TO AUTOMATE 
YOUR HOME; by David 
Gaddis. Home Automa- 
tion, USA, P.O. Box 
22536, Oklahoma City, 
OK 73123; Phone: 
405-840-4751; $29.95. 

Home automation, 
which promises better se- 
curity, convenience, lower 
operating costs, safety, en- 
tertainment, and fun, is one 
of the fastest growing 
areas of consumer elec- 
tronics. Encompassing 
home security, telephone 



HOW TO AUTOMATE 
YOUR HOME 

Ely Dzvki QmkjtM 



D D 



ffloo 




CIRCLE 338 ON FREE 

INFORMATION CARD 



and communications sys- 
tems, audio and video sys- 
tems, lighting and appli- 
ance control, and environ- 
mental (heating, cooling, 
sprinklers, pools) control, 
automating a new or exist- 
ing home requires quite a 
bit of information and fore- 
thought. This book con- 
tains valuable information 
on some of the most popu- 
lar present and proposed 
automation concepts, in- 
cluding X-10, CEBus rThe 
E!A's proposed standard, 
Consumer-Electronics 
Bus), Smart House, and 
Echelon. 

Combining technical in- 
formation with simple in- 
stallation requirements and 
recommendations, step- 
by-step project directions, 
and 115 illustrations, the 
book serves as an installa- 
tion guide as well as a refer- 
ence source. Because 
there are so many varia- 
tions and possibilities in 
home automation, the 
book is designed to pro- 
vide the information re- 
quired for readers to make 
decisions about their own 
requirements, based on 
cost, features, expan- 
dability and goals. 

Starting with an overall 
explanation of home auto- 
mation, the book goes on 
to detail home wiring re- 
quirements. The remaining 
chapters each address a 
particular part of a home- 
automation system and in- 
clude recommendations 
for basic and expanded 
systems and subsystems. 
Materials costs for the 
projects start as low as 
$28.00, and many cost 
less than $200 to install. 
The book includes $250 of 
coupons for discounts and 
free product offers. 



1991 TEST EQUIPMENT; 
from Amprobe Instru- 
ment, 630 Merrick Road, 
Lynbrook, NY 11563; 
Phone: 516-593-5600; 
Fax: 516-593-5682; free. 
Amprobe's full-line cata- 
log contains complete 
specifications and de- 
scribe the important fea- 
tures of its full line of 
electrical test equipment. 
Featured in its 48 pages are 
rotary scale clamp-ons with 
high-energy protection, 
digital mini clamp-ons, cir- 
cuit tracers, true-RMS 
strip recorders, digital 

AMPROBE 

199? Test Equipment 




U71W5 ThC .3 WJOMOt M BfCl tViMt, TEST *OLW*«*ir 

CIRCLE 339 ON FREE 
INFORMATION CARD 

megohmmeters, ultrasonic 
detectors, analog clamp- 
ons, digital tachometers, 
pyrometers, and record- 
ers. Convenient alpha- 
numeric model listings are 
provided, as well as color 
photographs, illustrations, 
and helpful hints, and sug- 
gested accessories and 
replacements. 

AN INTRODUCTION TO 
AMATEUR COMMUNI- 
CATIONS SATELLITES; 
by A. Pickard. Elec- 
tronics Technology To- 
day Inc., P.O. Box 240, 
Massapequa Park, NY 
11762-0240; $9.75, in- 
(continued on page 30) 



26 



Learn to Use Your 
Computer's Full Potential." 




New Career a 
Course from i 
CIE! 



IT 



If you've been hesitating about upgrading your 
computer skills becai.se you couldn't find the time or 
locate the right program to teach you everything you 
need to know to be successful in today's world of 
computers, you'll be happy to hear that CIE's new 
career course can provide you with the computer 
technology curriculum you seek in an independent 
study program you can afford to invest your time in. 

CIE's COMPUTER OPERATION and 
PROGRAMMING course was designed and devel- 
oped by CIE to provide a complete overall under- 
standing of the unlimited potential today's computers 
offer, once you learn and discover their full capabili- 
ties, in today's high tech environment. CIE's new 
computer course quickly provides you with the 
electronics fundamentals essential to fully understand 
and master the computer's technological potentials for 
your persona! and professional advancement. Upon 
mastering the fundamentals you will move into high 
level language programming such as BASIC and 
C-Language and then use that programming in order 
to relate the interfacing of electronic hardware circuitry 
to programming software. As a gradu- 
ate of the Computer Operation and 
Programming course, you will be able 
to successfully understand, analyze, 
install, troubleshoot, program and 
maintain the various types of electronic 
equipment used in business, manufac- 
turing, and service industries. 

Since 1934, CIE has been 
the world leader in home 
study electronics by 
providing our 1 50,000- 
plus graduates with the 
curriculum and hands-on 
training they've needed to 
become successful in 




today's highly competitive and computer oriented 
society. As a CIE student you'll receive a first rate 
education from a faculty and staff with only one 
desire. Your future success! 

We encourage you to look, but you won't find a 
more comprehensive computer course anywhere! 
And it's a course designed to fit 
around your lifestyle and commit- 
ments today, so you can be assured 
of professional successes and 
financial gains tomorrow. 

Please, do yourself a favor and 
send the attached card or fill out and 
mail the coupon below for more 
information about CIE's 

Computer Operation 
and Programming 
course. Do It 




Computer not 
included with 
course 



3 YES! I want to get started. Send me my CIE school catalog including details about the Associate Degree program 
(for your convenience, CIE will have a representative contact you - there is no obligation). 

Print Name 



AdJivss 
City 



Apt. 



State . 



.Zip , 



Age. 



Area Code/Phone No*. 



Check box for G.I. Bulletin on Educational Benefits □ Veteran 
[CLEVELAND 
INSTITUTE OF 
ELECTRONICS, INC. 

1776 East 17th Street • Cleveland. Ohio 44114' (216) 78 1 -9400 



////:«£ 



O Active Duty 




A, 



A school of thousands . 
A class of one. 
Since 1934. 



AE24 



C/3 

m 

m 
S 
en 
m 
21 



29 



Electmnics, DtfDDUQD 






APPLIANCE REPAIR HANDBOOKS— 13 

volumes by service experts; easy-to- 
understand diagrams, illustrations. For major 
appliances (air conditioners, refrigerators, 
washers, dryers, microwaves, etc.), elec. 
housewares, personai-care appliances. 
Basics of solid state, setting up shop, test 
instruments, $2.65 to $7.90 each. Free 
brochure APPLIANCE SERVICE, P.O. Box 
789, Lombard, IL 60148. (708) 932-9550. 
CIRCLE 84 ON FREE INFORMATION CARD 




SIMPLY SNAP THE WAT-50 MINIATURE FM 
TRANSMITTER on top of a 9v battery and 
hear every sound in an entire house up to 1 
mile away! Adjustable from 70-130 MHZ. Use 
with any FM radio. Complete kit $29.95 + 
$1.50 S + H. Free shipping on 2 or more! COD 
add $4. Call or send VISA, MC, MO. DECO 
INDUSTRIES, Box 607, Bedford Hills, NY 
10507. (914) 232-3878. 

CIRCLE 127 ON FREE INFORMATION CARD 




$495 FOR A PROGRAMMABLE DC 
POWER SUPPLY IS NOW A REALITY! 

• GPIB Interface Standard • Output Voltage/ 
Current Programming & Readback • Local & 
Remote GPIB Operations * Remote Sense 
Function • Programmable Overvollage and 
Overcurrent Protection • Software Calibra- 
tion • Superior Line/Load Regulation 

• Output Enable/Disable • 3 Year Warranty. 
FREE Orientation Video available. For de- 
tails, call: AMERICAN RELIANCE INC. 
800-654-9838 FAX: 818-575-0801. 

CIRCLE 180 ON FREE INFORMATION CARD 





THE MODEL WTT-20 IS ONLY THE SIZE OF 
A DIME, yet transmits both sides of a tele- 
phone conversation to any FM radio with 
crystal clarity. Telephone line powered - never 
needs a battery! Up to v* mile range. Adjusta- 
ble from 70-130 MHZ, Complete kit $29.95 
+ $1.50 S + H. Free Shipping on 2 or more! 
COD add $4. Call or send VISA, MC, MO. 
DECO INDUSTRIES, Box G07, Bedford 
Hills, NY 10507. (914) 232-3878. 

CIRCLE 127 ON FREE INFORMATION CARD 




CABLE TV CONVERTERS AND DE- 
SCRAMBLERS SB-3 $79.00 TRI-B1 $95.00 
MLD-S79.00 M35B $69.00 DRZ-DIC 
$149.00. Special combos available We ship 
COD, Quantity discounts. Call for pricing on 
other products. Dealers wanted, FREE CATA- 
LOG. We stand behind our products where 
others fail. One year warranty. ACE PROD- 
UCTS. P.O. Box 582, Saco, ME 04072 
1 (800) 234-0726. 
CIRCLE 75 ON FREE INFORMATION CARD 



CALL NOW 
AND 

RESERVE 
YOUR SPACE 

• 6 x rate $940.00 per each insertion. 

• Fast reader service cycle. 

• Short lead time for the placement of 
ads. 

• We typeset and layout the ad at no 
additional charge. 

Call 516-293-3000 to reserve space. Ask 

for Arline Fishman. Limited number of 
pages available. Mail materials to: 
mini-ADS, RADIO-ELECTRONICS, 500- 
B Bi-County Blvd., Farmingdale, NY 
11735. 

FAX: 516-293-3315 






NEW LIT 



continued from page 26 



eluding shipping and 
handling (order No. 
BP290). 

Unless you work for a 
major telecommunications 
company, the space pro- 
gram, or the military, com- 
munications and broadcast 
satellites are normally off 
limits to you. Even if you 
own a satellite-TV receiver, 
you cannot participate in 
the technical aspects of 
those communications- 
satellite systems. There 
are, however, a large 
number of amateur com- 
munications satellites or- 
biting the earth. Those can 
be tracked, and their sig- 
nals received, by ordinary 
people using relatively in- 
expensive equipment. This 



An Introduction to 

Amateur 
Communications 

Satellites 




CIRCLE 340 ON FREE 
INFORMATION CARD 

book describes several 
systems, how they can be 
connected to a computer, 
and how to use them. The 
decoded signals contain 
such information as tele- 
metry data and weather 
pictures. The book is de- 
signed to encourage read- 
ers to become actively 
involved in receiving and 
decoding signals from am- 
ateur communications sat- 
ellites, using aspects of 
electronics, engineering. 
I and science. R-E 












Now, You Can Eavesdrop On The World. Introducing the new Drake R8 Communications Receiver. 
It's world class, world band radio, madcin the U.S.A. From Perth to the Persian Gulf, Moscow to 
Mozambique, local or global, you hear events as they happen with amazing clarity. Since 1943, Drake 



_._ 1 


1 


A3 Comniniciiwi KKnuf UfWfB 


■-"! 






HMt 




- 


ino« *Un*i 


rcM« — •> — wore* — ■ . . .. 

I * t* * 


» 


__ . Muficw^^h— J***^" rat — Q—m 




■ 


■ ^ ^. 





" 


v 



has been setting the standards in electronic communications. . .and then raising them. Today, there's 
no better shortwave receiver than the Drake R8. Out-Of-This-World Performance. The new Drake R8 
has more standard features than other shortwave radios. You get wide frequency range (100 KHz to 
30,000 KHz), coverage of all world and local bands, and excellent dynamic range. But you also get 
important features you won't find on receivers costing hundreds of dollars more. A multi- voltage 
power supply. Pre-amp and attenuator. Five filter bandwidths and synchronous detector. Dual mode 
noise blanker and passband offset. Non- volatile 100 channel memory. All designed to give you the best 
reception with the least distortion. Down-To-Earth Design. The ergonomic design of the R8 gives you 
real ease of operation. You have convenient keypad entry, with large, legible controls. The face is bold. 
Uncluttered. And the liquid crystal display (LCD) is backlighted for easy reading. Try The R8. . . 
At Our Risk. If you're not impressed by Drake's quality, performance and ease of operation, return 
the R8 Receiver within 15 days and we'll refund your money in full, less our original shipping 
charge. For more information, or to order, call TOLL-FREE, 1-800-9-DRAKE-l. Telephone orders 
may be placed on a major credit card. $979.00 (Shipping and handling $10 in continental U.S. 
Ohio residents add 6>/2% tax.) Call TOLL-FREE, 1-800-9-DRAKE-l today. You can't lose. 






DRAKE 

In touch with the world. 
R.L. Drake Company ■ P.O. Box 3006 • Miamisburg, Ohio 45342 U.S.A. 

CIRCLE 177 ON FREE INFORMATION CARD 







48 HOUR 
SHIPPING 



ELENCO & HITACHI PRODUCTS 
AT DISCOUNT PRICES 



48 HOUR 
SHIPPING 



Hitachi RSO Series 

{Portable Real-lime Digital Storage Oscilloscopes) 

VC-6023 - 20 MHz, 20MSrs $99/mo* 

$120/ mg* 

$ 1 35/rr «/ 

$125Ano- 

$200/mo* 



VC-6024 - 50 MHz, 20MS/S _ 
VC-0025 • GOMHz, 20MG/s_ 
VC-6045 ■ 100MHz. 40MS/S 



LEASING AVAILABLE 
For all Hitachi Scope* - Call for dslalli 
■ Based on 24 months except V-1 150, VC-EM5, VC- 
6145 (36 months) 



VC-6145 ■ 100MHz, 100MS/S 

RSO's from Hltectrl leature noil mode, averaging, save 
memory, smoothing, interpolation, pretriggering, cursor 
measurements. These scopes enable more accurate, 
simplier observation of complex waveforms, in addition to 
such functions as harccopy via a plotter interface and 
waveform transfer via the RS-232C interface. Enjoy (he 
comfort ol analog and the powar to digital. 

20MHz Elenco Oscilloscope 

$375 

M 0-1251 

* Dual Trace 

Componanl Tesier 

• «■ CRT 

• X-Y Operalion 

• TV Sync 

• 2 P-1 Probes 



Hitachi Portable Scopes 

DC to SQMHz, 2-Channet. DC offset func- 
tion, Alternate magnifier function 
V-52S - CRT Readout, Cursor Meas. _ *1.025 

V-523 - Delayed Sweep . $995 

V-522 - Basic Model $895 

V-422 - 40MHz $795 

V-223 - 2QMhz delayed sweep $695 

V-212 - 20MHz $425 



HITACHI COMPACT SERIES SCOPES 

This series provides many new functions such as CRT 
Readout. Cursor measurements [V-10S5/1065V665), Fre- 
quency Ctr (V-1 035), Sweeptime Auforanging, Delayed 
sweep arid Tripper LocH using a 6-Inch CRT, You don' t feel 
the compactness in terms of performance and ope ration. 



V-660 ■ 60MHz, Dual Trace 

V-665 - 60MHz, DT, w/eursor 

V-1 060- 100MHz. Dual Trace 

V-1 065- 100MHz. DT, w/cursor_ 
V-10B5 - 100MHz. QT. wteursorl 
V-1 1 0OA - 100MHz. Quad Trace_ 
V-1 150 - 150MHz. Quad Trace 



$1,195 
"$1,345 
_$ 1.425 
_$105/mo* 
_$125/mo- 
_S12o7mo' 
_$115^mo- 



Elenco 35MHz Dual Trace 

50MHz D**33 
MO- 1252 

• High luminance 6' CRT 

■ 1 mV Sensitivity 

« 6KV Acceleration Voltage 

• 1 0ns Rise Time 

• X-Y Operalion • 1 Axis 
• Delayed Triggering Sweep 

• Includes 2 P-1 Probes 

All scopes include probes, schematics, operators manual and 3 year (2 yrs for Elenco scopes) world wide warranty on parts * labor. Many accessories available for all Hitachi 
scopes. Call or write for complete specifications on these and many other fine oscilloscopes. 




FREE DMM 

with purchase of 

ANY SCOPE 



SCOPE PROBES 

P-1 65MHz, ix, lOx $19.95 
P-2 100MHz, Ix, lOx $26.95 




B + K 

TEST EQUIPMENT 
All Models Available 

Call for special price 



Digital Capacitance Meter 

CM-1550B 

$58.95 

9 Ranges 
,1pl-20,000utd 

.5% basic accy. 

Zero control wr Case 

Big 1' Display 




Digital LCR Meter 
LC-18Q1 



$125 




Measures: 
Coils 1uH-2O0H 

Caps • p: -2uCiul 
Res .01-20M 




M&g 



Big 1" Display 



Multimeter with 
Capacitance & 
Transistor Tester 

$55 CM-1S00S 

Reads Volts, Ohms 

Currenl, Capacitors, 

Transistors and 

Diodes / wilh case 



FLUKE 

MULTIMETERS 
All Models 
Available 

Call far special price 



Quad Power Supply XP-580 

$59.95 

2-20V 2A 

12V g 1A 

5V0 3A 

-5V @ 5A 

Fully regulated and short circuit protected 




Triple Power Supply XP-620 

Assembled $69 
Kit 145 

2 to 15V @ 1A. 
-2 to -15V @ 1A 
for 4 to 30V 01 A) 
and 5 V if 3A 
All the desired features lor doing experiments. 
Features short circuit protection, all supplies 




AM/FM Transistor 
Radio Kit 

with Training Course 

Model AMVFM 108 

$26.95 

14 Transistors * 5 Diodes 
Makes a greet school project 




True RMS 4 1/2 
Digit Multimeter 
M-7Q00 

1 35 

,05% DC Accuracy 
.1% Resistance 

vrii! Freq. G:: j ii Inl- 
and Deluxe Case 



$1: 



o 



D 
< 



32 



GF-8016 Function Generator 

with Freq. Counter 



jnrfftKJl 



$249 



Sine, Square, Triangle 
Purse, Ramp. ,2 to 2M Hi 
Freq Counter .1 • 10MH* 



GF-B01 5 without Freq. Meter SI 79 



Function Generator 
, ,;,-' , Blox 

"...~^~| $28.95 

Provides sine, triangle, square 

weve from 1 Hz to 1 MHz 

AM or FM capability 



Learn to Build and Program 
Computers with this Kit 

Includes: Ail Parts. Assembly and Lesson Manual 

Model 
MM-8000 



Wide Band Signal 
Generators 




$129.00 




Starting from scratch you build a cample to system. Our 
Micro- Waster traifior teaches you to writs into RAIvte, 
ROMs and run a 8065 microprocessor, which uses 
similar machine language as IBM PC. 

Robotics Kit for above (MMS010) 71.95 



WE WILL NOT BE UNDERSOLD! 
UPS Shipping: 48 States 5% 
(S3 Min $10 Max) Shipping 
IL Res., 7% Tax FAX: 708-520-0085 



SG-90QO $129 

RF Freq 1 0OK-iSOMKz AM Modula- 
tion of IKHz Variable RF output 
SG-9500 *l Digital Display & 
150MHz built-in Counter $249 



XK-500 DIGITAL / ANALOG TRAINER 

A complete mlnl-lab for bu Idlng, losling, prototyping analog and digital circuits 
Elencc's Digital ■' Analog Tnlntr ht SpOCiaJly dtslgntd *or KhQfll project-., wlbti 5 bullE-M pCUCf SuppUOS 
Includes a lunctom gflUMKator wilh o&Mlnously vanfttfo. sine, Wanrjulaj'. jc-taurj wito Inrmi. AB powtr 
£i4*Uios ara rogulatad and pfOlodod agi^S! Bflfina. 

POWER SUPPLIES 



■ ,1.25 to MVtJC 4 .£ fcrp 

1*1 2510 ISVDC $ 1 **vi 
.-VI5!l-KViXS 5'-*nnj 

M.Ktt-lWCCe>tAnipi 
. -i 1 VDC * ' Amp 

* -:2VL-Z3 1 Arc 
*-SVDCS 1Ar-C 

» HV.AC CtnrH- UfOfd & 1SVAC 

rilAmp 
ANALOG -SECTION 

■ FuWIian BUM raftr 5Jn#, Tnjngjlar. 
Squariwavi'lDirnt 

■ FiKfJffftcy adi-j^arjln *\ I vd rOADIl 
■mm 1 ID 10CKHZ 

• FlfHtlrrjqirtnciri^iiiM 

* Amplbid* KKM 

• DCaflM 

> Modulation FM-AM 

DIGITAL - SECTION 

■ Eijtt data. r**cft« 

♦ TWO nrj bWrftM bcjc IrirtCrhM 

* EqN LEO '*aowi * TTL Ojirgr^ 

♦ C*x* ftrtqutfCy T w l WKHZ 

■ Clock 1/TrfifuM SVPF* tqniit wi>* 

BREADBOARDS 



(VU t* poutf ItEtal 1.6B0I 




C & S SALES INC. K' 

1245 Rosi!\vooa.rieerfielrL II. 60015 L — =^ 
1800)292-771] 1708) 541-0710 



15 Day Money Back Guarantee 

2 Year Warranty ?,Ka subject w change 

WRITE FOR FREE CATALOG 



CIRCLE 109 ON FFtEE INFORMATION CARD 



Our solid-state Teste 

coil can produce 

sparks as long as 8 

inches with a peak 

output of about 100,000 volts. 



SOLID STATE 



LA COIL 




DUANE A BYLUND 



Tesla coils have been around for 
almost 100 years and, with the 
exception of vacuum-tube driven 
coils, not much has changed from 
the way Nikola Tesla invented them. 
This article describes a new type of 
Tesla coil; a true solid-state Tesla coil. 
One thing that makes our Tesla coll 
unusual is that the coupling to the 
secondary coil is by a direct electrical 
connection rather than by magnetic 
fields. Direct coupling is not new to 
Tesla coils but it is seldom seen. 

The solid-state Tesla coil is by no 
means as spectacular as capacitive- 
discharge Tesla coils but it gives just 
as good, or better, performance as a 
vacuum-tube Tesla coil. Sparks as 
long as 8 inches are possible with a 
power-line consumption of 2 amps at 
120 volts (see Fig. 1). and the output 
reaches a peak of about 100,000 
volts. Although the average power in- 
put to the device is around 250 to 300 
watts, the peak input power to the 
Tesla secondary coil is about 800 
watts. The Tesla coil is an excellent 
teaching tool, as many interesting 
things may be learned with the aid of 
this device. 

Circuit description 

The schematic for the solid-state 
Tesla coil is shown in Fig. 2. The sec- 
ondary of the Tesla coil, when directly 
driven by a solid-state driver, appears 
like a series RLC circuit. That's due to 
the self-capacitance of the coil with 
respect to ground. The capacitance is 
normally very small with the induc- 
tance being fairly large. At the reso- 
nant frequency, the inductive reac- 
tance cancels the capacitive reac- 
tance. The effective impedance is 
limited by such losses as the DC re- 
sistance of the coil, AC skin effect of 




m 

TJ 

H 

m 

no 
m 



33 



CO 

o 

z 
O 
ir 
F 
o 

LU 

I 

UJ 

6 

Q 
< 



the wire, eddy currents induced 
in nearby objects by the field of 
the coil, and so on. 

Series RLC circuits have rela- 
tively low impedances when oper- 
ated at the resonant frequency. 
The coil used in this project, 
when operated at its resonant fre- 
quency, looks tike a 450-ohm re- 
sistive load to the solid-state 
driver. Series RLC circuits pro- 
duce high voltages on the induc- 
tor and capacitor at the resonant 
frequency. The high voltage is 
due to a high current flowing 
through a high reactance (re- 
member that the inductance is 
large and the capacitance is 
small, creating large reactances 
in each component at a given fre- 
quency). That is what produces 
the corona discharge at the end 
of the secondary coil. 

The heart of the driver is IC1. 
the SG3524 pulse-width modu- 
lator. The duty cycle is fixed at 
about 45 % for best efficiency. The 
frequency is controlled by the re- 
sistance on pin 6 and the capaci- 
tance on pin 7. With the values 
shown, the frequency has a 
range from 200 to 240 kHz. A flip- 
flop inside the chip divides that 
by 2 so that the effective output of 
the driver has a range from 100 to 
120 kHz. 

The outputs on pins 12 and 13 
are 180 degrees out of phase with 




Warning!! This article deals with and 
involves subject matter and the use of 
materials and substances that may be 
hazardous to health and life. Do not at- 
tempt to implement or use the information 
contained herein, unless you are experi- 
enced and skilled with respect to such 
subject matter, materials, and sub- 
stances. Neither the publisher nor the au- 
thor make any representation as for the 
completeness or accuracy of the informa- 
tion contained herein, and disclaim any 
liability for damages or injuries, whether 
caused by or arising from the lack of com- 
pleteness, inaccuracies of the informa- 
tion, misrepresentations of the directions, 
misapplication of the information, or other- 
wise. 

each other, and drive the gates of 
MOSFETs Ql and Q2, which, in 
turn, drive the primary of trans- 
former Tl. Transformer Tl drives 
the bases of switching-tran- 
sistors Q3 and Q4. The compo- 
nents in the base circuitry are 
used to increase the switching 
speed of the transistors. Tran- 
sistors Q3 and Q4 switch the line 
voltage across the primary of T2, 
which increases the voltage and 
drives the end of the secondary 
coil directly. Note that the line 
voltage delivered to T2 is half- 
wave rectified by Dl. That is im- 
portant to the operation of the 
Tesla coil because a pulsating 
voltage is needed to produce the 
best effects. 

When the device is plugged 
into a wall receptacle it will be in 
its standby mode. That is, the 21- 
volt power supply will be opera- 
tional and the FETs will be driv- 
ing the primary of Tl. The 
standby mode produces enough 
power to "tune" the driver to the 
coil's resonant frequency before 



full power is applied. (Remember 
that the resonant frequency can 
be affected by nearby objects.) 
The current supplied to the sec- 
ondary coil is indicated by LED1. 
Tuning is accomplished by ad- 
justing the frequency via Rl and 
observing LED1. When reso- 
nance is achieved, the secondary 
coil will have a low impedance 
which will produce maximum 
current, lighting the LED. Di- 
odes D3-D6 limit the forward 
and reverse voltages on LED1 
when in the high -power mode. 
(Note that you must use an LED 
that lights at 1.5 volts — some 
LED's, including most green 
ones, need 2.1 volts or higher. 

When the device is switched 
into the operating mode (or the 
high-power mode), half-wave 
line-voltage pulses will be applied 
to the primary of T2. As the half- 
wave voltage increases, the cur- 
rent in the secondary coil in- 
creases and the energy stored in 
the inductance and capacitance 
of the secondary coil will in- 
crease. During this time there is 
no corona from the secondary 
coil (if the coil is constructed as 
shown in this article). Sometime 
before the half-wave line voltage 
reaches its peak, the corona will 
appear on the secondary coil, 
which will dissipate the stored 
energy very quickly. During the 
remainder of the half-wave line 
voltage, the coil will produce cor- 
ona but the energy level will not 
be as great as the initial dis- 
charge. The coil will produce six- 
ty individual corona discharges 
every second, although you'il see 
a continuous discharge. 



FIG. 1— THE SOLID-STATE TESLA COIL 
can produce sparks as long as 8 inches. 
The output reaches a peak of about 
100,000 volts. 




USE THIS FOIL PATTERN, shown half-size, to etch your own PC board. 



34 




FIG. 2— SCHEMATIC FOR THE SOLID-STATE TESLA COIL. The secondary of the Tesla coil 
appears like a series RLC circuit due to the sell- capacitance of the coil with respect to 
ground. 







All resistors are Vi-watt, 5%, un- 
less otherwise indicated. 

R1— 1000 ohms, 10-turn 

potentiometer 
R2— 3900 ohms 
R3, R4—2200 ohms, Vz watt 
R5, R6— 2200 ohms 
R7— 330 ohms, 1 watt 
R8, R9— 0.56 ohms, 2 watts, 

flameproof 
R10, R11— 3300 ohms 
Capacitors 

CI— 0.001 jiF, 50 volts, 5%, polyester 
C2 — 110 pF, 50 volts, polyester 
C3, C4— 10 p.R 35 volts, tantalum 
C5— 330 |xF, 35 volts, electrolytic 
C6, C7— 2 m-F. 200 volts, nonpolar 

film-type 
C8, C9— 0.02 ^R 1000 volts, ceramic 

disc 
Semiconductors 

IC1 — SG3524 pulse-width modulator 
D1— MR751 diode 
D2-D6— 1N4934 diode 
D7, D8—1N4936 diode 
D9 — not used 
D10-D17— 1N4004 diode 
Q1 . Q2— SK9155 power MOSFET 



PARTS LIST 

Q3, Q4— 2N6678 or SK9140 NPN 
transistor 

LED1— red LED. See text 

Other components 

F1 — 3-amp, 250-volt, fast-blow fuse 

BR1— VM08 bridge rectifier, Varo 

T1 — hand-made transformer (the 
core is TDK # PC30EER25.5-Z 
and the bobbin is TDK # 
BEER-25.5-118CP) 

T2 — hand-made transformer (the 
core is TDK # PC30EC70-Z and 
the bobbin is TDK # BEC-70-5116) 

T3 — hand-made transformer (the 
core is TDK # PC30EER25.5-Z 
and the bobbin is TDK # 
BEER-25.5-118CP) 

T4— 11 5VAC/15VAC center-tapped 
transformer (Triad F-132P) 

S1— SPST key switch 

Miscellaneous: enclosure, alumi- 
num angle bracket, high-voltage 
wire {to connect main unit to Tesia 
secondary), 30-gauge magnet wire 
for Tesla secondary and L1 and L2. 
24-gauge magnet wire for L3 and 
L4, 18-gauge stranded hook-up 
wire for L5 and L6, 15-gauge mag- 



net wire for T2 primary, 26-gauge 
hook-up wire for T2 secondary, 18- 
gauge magnet wire for both wind- 
ings of T3, brass rod. discharge 
ball, hardware, AC linecord, etc. 

Note: TDK ferrite cores and bob- 
bins are available from MH&W 
International, 14 Leighton Place, 
Mahwah, NJ 07430, (201) 
891-8800. The following items 
are available from Corona Coil, 
PO Box 474. Riverton, UT 84065: 
• T1— $15.00 

T2— $38.00 

T3— $12.00 

T4— $14.00 

Tesla secondary coil— S50.00 

PC board— $15.00 

Aluminum angle bracket 
(heatsink and PC-board 
mount) — $5.00 
A 124-page book by the author. 
Modern Tesla Coil Theory, is 
available for $16. 
Please add S15 S&H tor the Tesla 
secondary, and 10% S&H for all 
other items. 






W 



s 

Co 

— 



35 



TESLA 
SECONDARY 




FIG, 3— PARTS-PLACEMENT DIAGRAM. It's best to play it safe and use the PC 
this project; we've provided the toil pattern it you would tike to etch your own 



board for 
board. 



Construction 

Most of the construction is fair- 
ly simple if the printed circuit 
board is used. A parts-placement 
diagram is shown in Fig. 3, and 
we've provided the foil pattern if 
you would like to etch your own 
board. Figure 4 shows the com- 
pleted prototype board housed in 
its aluminum enclosure. 

The most difficult item to con- 
struct will be the Tesla secondary 
coil, followed bv Tl and T2. The 



secondary coil may take an hour 
or so to make if you prepare 
ahead of time. Preparation in- 
cludes making some device that 
will easily rotate the coil form 
while winding the wire. The au- 
thor used a small lathe and it 
look about 15 minutes of actual 
winding time and 30 minutes to 
get set up. 

Do not deviate at all from the 
following parameters of the sec- 
ondary coil! Any deviation will 



(0 

o 

z 
o 
rn 

& 

LU 

_i 

LU 

6 
q 
a 
x 




FIG. 4— HERE'S THE AUTHOR'S COMPLETED PROTOTYPE housed in its aluminum 
enclosure. It's important that the case be properly grounded. 



change the characteristics of the 
coil and it may not operate with 
the driver unless modifications 
in the driver are made. Any 
change in physical dimensions 
or wire size will alter the resonant 
frequency and effective imped- 
ance of the coil. Any change to 
the discharge electrode will effect 
the maximum energy obtainable. 

The coil form for the secondary 
winding is a standard 5-gallon 
plastic container 10 inches in di- 
ameter at the bottom, 12 inches 
in diameter at the top, and 14 
inches long. The bottom of the 
container becomes the top of the 
coil. To make winding easier you 
should drill a hole about an inch 
in diameter through the center of 
the bottom of the container. A 
similar hole should be drilled 
through a removable lid and then 
the complete coil form can be ro- 
tated easily on a dowel. Start the 
secondary winding 1 inch from 
the small-diameter end and 
close-wind 30-gauge magnet wire 
for a total length of 10 inches. It 
does not matter what direction 
the wire is wound in. 

When winding the original coil 
for this article, shellac was used 
to lubricate the wire as it was 
wound and also to act as a sea- 
lant afterwards. It was difficult to 
wind the coil because the coil 
form was very slick and had a 
slight taper to it and, as a result, 
the wire kept slipping. It may be 
easier to spray the container with 
adhesive before winding the wire 
to make it stay in place. A couple 
of coats of shellac should be ap- 
plied to the finished winding. You 
also must put 3 or 4 beads of sil- 
icone sealant around the end of 
the winding at the top of the coil 
to keep corona discharges away 
from the area. If corona dis- 
charges appear along the coil at 
the top it will limit the maximum 
energy and destroy the coil form. 

The discharge ball, or elec- 
trode, is a brass-plated metal 
doorknob, 1-inch in diameter, 
that can be found in hardware 
stores (see Fig. 5). The ball is 
mounted on a 4-inch brass rod; 
you can drill and tap the ends of 
the brass rod with a 6-32 tap (or 
whatever matches the threading 
on the doorknob) to make 
mounting easier. The brass rod is 
connected to the coil form by two 
pieces of plastic, one on each side 
of the coil form, over the '/2-inch 



36 




FIG. 5— THE DISCHARGE BALL is a brass-plated metal doorknob, 1-inch in diameter. The 
ball is mounted on a 4-inch brass rod that's been tapped to make mounting the ball easier. 



hole. A 6-32 screw passes 
through the pieces of plastic and 
into the brass rod to hold the as- 
sembly together. The wire is sol- 
dered to a lug held in place by the 
6-32 screw. 

A banana jack is used to make 
connections at the bottom of the 
coil. Locate the jack about 3 A- 
inch from the edge of the wire on 
the coil. Silicone should be used 
to insulate the connections be- 
tween the magnet wire and the 
brass rod and banana jack. The 
finished coil, when built exactly 
as we've shown, will have a reso- 
nant frequency of about 110 kHz. 

Transformer Tl is made with a 
ferrite core and bobbin from TDK 
(see the parts list). Coils LI and 
L2 are wound first with 30-gauge 
magnet wire. 16 turns each, 
making one layer on the bobbin. 
The two windings are bifilar 



wound, as shown in Fig. 6-a; LI 
starts on pin 3 and L2 starts on 
pin 4. Wind both in a coun- 
terclockwise direction while look- 
ing at the top of the bobbin. 
Terminate LI on pin 1 and termi- 
nate L2 on pin 2. Put a layer of 
cellophane tape on top of the 
winding to insulate it from L3 
and L4. 

Coils L3 and L4 are made with 
5 turns each of 24-gauge magnet 
wire and are also bifilar wound, 
on top of LI and L2, and in the 
same direction. Coil L3 starts on 
pin 6 and L4 starts on pin 8. Ter- 
minate L3 on pin 5 and terminate 
L4 on pin 7. This completes the 
transformer until it is mounted 
on the PC board. 

Put the two core halves 
through the bobbin and put tape 
around them to hold them in 
place. As shown in Fig. 6, L5 and 



L6 are wound after the trans- 
former is mounted on the board; 
L5 and L6 are wound with 18- 
gauge stranded hook-up wire 
with one turn each. Solder the 
collector (Q4) end of L6 to the PC 
board. Go one turn in a coun- 
terclockwise direction around 
the core of Tl and then terminate 
the other end of L6 at the primary 
of T2. Solder the collector (Q3) 
end of L5 to the PC board and go 
in a clockwise direction around 
the core of Tl for one turn, termi- 
nating the winding at the cath- 
ode of Dl. 

Transformer T2 is also made 
from a ferrite core and bobbin 
from TDK (again, see the parts 
list). The primary is 10 turns of 
15-gauge magnet wire, although 
a smaller gauge, say 18, can prob- 
ably be used. It does not matter 
what direction the wire is wound 
in but the turns should be equal- 
ly spaced across one layer of the 
bobbin. Put several layers of cel- 
lophane tape on top of the pri- 
mary to insulate it from the 
secondary and to provide a 
smooth surface on which to wind 
the secondary. The secondary is 
made with 280 turns (the exact 
number is not critical) of 26- 
gauge hook-up wire. The direc- 
tion is unimportant. You can use 
magnet wire if you desire but you 
should put cellophane tape be- 
tween each layer. The low-voltage 
end of the secondary is the one 
that is the closest to the primary 
winding. When the windings are 
complete, put the core halves 
through the bobbin and hold 
them in place with tape wrapped 
around them. 

Transformer T3 is made with 
the same core and bobbin as Tl. 
Both windings are bifilar with 18- 
gauge magnet wire for as many 
turns as possible. The start of 
both windings are polarized as 
indicated by a dot in the sche- 
matic diagram (Fig. 2). The pins 
on the bobbin are not used and 
should therefore be cut off, and 
the 18-gauge wires are then sol- 
dered directly to the PC board as 
indicated. 

An aluminum angle bracket is 
used when mounting switching- « 
transistors Q3 and Q4. The tj 
bracket provides the physical rn 
support between the PC board cd 
and enclosure and also provides 3 
good heat sinking for the tran- ^ 
sistors. The transistors should iS 



37 




FIG. 6— TRANSFORMER T1 IS MADE by winding coils L1 and L2 first {a). After putting a 
layer of cellophane tape on top of the first windings, coils L3 and L4 are wound on top of L1 
and L2. Coils L5 and L6 are wound after the transformer is mounted on the board (b). See 
text for detailed instructions. 



be insulated from the aluminum; 
Insulating hardware is normally 
included when you purchase the 
transistors. Use the PC board as 
a template for drilling holes for 
the transistors in the aluminum 
bracket. The angle bracket is 
mounted to the enclosure by dril- 
ling holes and taping them with a 
6-32 tap. Thermal conductive 



O 

z 

o 

o 



W 

Q 

Q 
< 
II 




FIG. 7— SEEN HERE IS THE DISCHARGE 
from the ball electrode into the air. 



compound is used between the 
transistors and angle bracket 
and between the angle bracket 
and the enclosure. 

A banana jack is mounted in 
the back of the enclosure to make 
connections between the Tesla 
secondary coil and the high- volt- 
age ferrite transformer. The out- 
put voltage from the ferrite 
transformer may reach 5000 
volts peak with no load so it is 
wise to use extra insulation for 
the banana jack. Mount a piece of 
plastic, IVi-inch square, to the 
back of the enclosure over a 1- 
inch square hole, and rnotmt the 
banana jack in the center of the 
plastic. That will space the ba- 
nana jack at least l /a-inch from 
the metal enclosure. 

The prototype used a 10-turn 
potentiometer for Rl to make fre- 
quency adjustments easier and 
this allowed the use of a 10-turn 
dial to mark the frequency set- 
tings for different purposes. You 
can use a regular potentiometer 
but the 10-turn unit is superior. 

An enclosure was fabricated 
out of Vs-inch aluminum with a 
plexiglass top, but any metal en- 
closure would be suitable. Just 
be absolutely sure that you 
ground the metal enclosure. 



Operation 

Warning: The power output 
from the Tesla coil is dangerous! 
Make sure no one comes in con- 
tact with the output voltage di- 
rectly from the driver. Make sure 
nobody tampers with the unit, 
and keep it out of reach of chil- 
dren. Make sure you use a key 




FIG, 8— THE SPARKS WILL JUMP even 
farther if a grounded electrode is placed 
near the discharge ball. 



38 



switch to turn power on and off to 
prevent someone from getting in- 
jured, and keep the key in a safe 
place. 

Caution: All components on 
the secondary of Tl are not iso- 
lated from the power line. Use 
caution when measuring values 
in this area. You must isolate an 
oscilloscope from ground if mea- 
suring in this area. Make sure 
you use a three-prong power cord 
and that the case of the driver is 
well grounded. Also, make sure 
you plug the unit into a well- 
grounded electrical outlet. 

Double check all wiring to 
make sure it is correct. Make sure 
the operate switch is in the 
standby position (line voltage 
disconnected from Dl). Using a 
digital voltmeter isolated from 
ground, measure the voltage 
across C3 and C4. If everything is 
working correctly in the low-volt- 
age circuitry, there should be 
about 2.5 volts across those ca- 
pacitors. If that voltage is not 
present you should check the 21- 
volt power supply. Make sure that 
5 volts is on pin 16 of IC1. If the 
oscillator is working correctly 
you should have about 3.6 volts 
on pin 6 of IC1. 



Connect the Tesla secondary 
coil to the driver with a 3-foot 
insulated wire (it is a good idea to 
keep at least 3 feet from the sec- 
ondary coil). You should always 
unplug the driver when you are 
making connections between the 
driver and secondary coil to be 
absolutely safe. The wire con- 
necting the coil and driver car- 
ries a dangerous amount of 
power so be certain the wire is 
well insulated. In a dimly lit room 
you should be able to adjust the 
tune control to set the driver at 
the coil's resonant frequency. Ob- 
serve the LED and watch for one 
place in the tuning control's ad- 
justment where the LED glows 
brighter than anywhere else. 
Never apply full power to the driv- 
er unless you can obtain reso- 
nance first. Damage to the driver 
will most likely occur if reso- 
nance is not maintained. 

Once you obtain resonance you 
can switch to the full-power 
mode; the LED will glow very 
brightly. With no objects around 
the coil you should observe a 
snappy brush discharge 5 to 6 
inches in length emanating from 
the discharge electrode (see Fig. 
7). It might be somewhat louder 



than you would expect. Very 
slight adjustments in the tune 
control may improve the dis- 
charge. You should be able to get 
7-Inch streamers with a 
grounded electrode above the coil 
(see Fig. 8). Be aware that any 
change of the physical surround- 
ings around the coil will change 
its resonant frequency and the 
tune control will need to be ad- 
justed to maintain resonance. 
When operating the Tesla coil, be 
aware of the temperature of the 
enclosure where the aluminum 
angle bracket is mounted. Shut 
off the power if the area gets too 
warm. The prototype was oper- 
ated for 2 full minutes, and you 
could just start to feel some 
warmth on the enclosure. How- 
ever, you should operate the Tesla 
coil only for short periods of time. 
Once you have a working unit 
you can start to experiment with 
different things. Try removing 
the discharge ball and use a point 
instead. Try changing the dis- 
tance of the ball electrode from 
the coil. Try holding an incandes- 
cent lamp a short distance from 
the coil — but be very careful. Dif- 
ferent lamps will produce dif- 
ferent discharges. r-e 



* FCC NO-CODE ' 

AMATEUR RADIO LICENSE 

The FCC recently passed Docket 90- 
55 which for the first time allows a new 
codetess entry ham radio license of 
technician grade. Privileges 30 MHz 
and above — All modes! (See R.E. ar- 
ticle in April 1991 issue). 

Get all the no-code license details, 
study & testing information plus a one- 
year subscription to one of ham radio's 
longest running specialty mode publi- 
cations that will teach you all about the 
new modes you will be able to operate! 

FSTV SSTV FAX RTTY PACKET 
AMTOR OSCAR FM REPEATERS 
MICROWAVE AND LOTS MORE! 



SEND 

$25 

CHECK 

OR 
MONEY 
ORDER 



L 



si'i:c-com 



1 



M. 




OUR 

24TH 

YEAR 

SINCE 

1967! 



I 



The SPEC-COM Journal 

P.O.Box 1002, 

Dubuque, IA 52004 

(319)557-8791 

MC--vis*(S*add«iJ 











I fttfl 



CIRCLE 108 ON FREE INFORMATION CARD 




EARN YOUR 

B.S.E.E. 
DEGREE 

THROUGH HOME STUDY 

Our New and Highly Effective Advanced-Place- 
ment Program for experienced Etectronic Tech- 
nicians grants credit tor previous Schooling and 
Professional Experience, and can greatly re- 
duce the time required to complete Program and 
reach graduation. Mo residence schooling re- 
quired for Qualified Electronic Technicians. 
Through this Special Program you can pull all of 
the loose ends of your electronics background 
together and earn your B.S.E.E. Degree. Up- 
grade your status and pay to the Engineering 
Level. Advance Rapidly! Many finish in 12 
months or less. Students and graduates in all 50 
States and throughout the World. Established 
Over 40 Yearsl Write tor free Descriptive Lit- 
erature. 



GI 



4251 CYPRESS DRIVE 
JACKSON, MISSISSIPPI 39212 



COOK'S INSTITUTE I 

OF ELECTRONICS ENGINEERING E 



CIRCLE 58 ON FREE INFORMATION CARD 



39 




Spectrum 




r 



DAN DOBERSTEIN AND JOHN CARDONE 



C/5 

m 
-v 

-t 
m 
£ 

m 

3) 



40 



LAST MONTH WE DISCUSSED THE 

theory behind our PC -based 810- 
MHz spectrum analyzer. This 
month, we'll show you how to 
build it and discuss the software 
used to operate the instrument. 
Before we get into the con- 
struction, let's start off with a de- 
scription of the setup and 
operating software. All executa- 
ble files we mention here can be 
downloaded from the Radio- 
Electronics BBS (516-293-2283, 
1200/2400. 8N1. file SPEC- 
AN.ZIP). Even before you build 
the analyzer, we would recom- 
mend that you download and run 
the software, (It will run even 
without the board installed.) 
Even though you won't get any 
meaningful data, it will help you 
to understand exactly how the 
software operates. 

Software and operation 

Before you can use the spec- 
trum analyzer, some software set- 
tings must be initialized so that 
the host computer will know at 
what address the analyzer re- 
sides, which printer port will be 
used, and the type of printer that 
will be used. The initialization is 



performed with SETUPEXE, 
which is a stand alone program 
that must be executed outside of 
the main program menu. The de- 
tails of using SETUP are covered 
in the README.DOC file. SETUP 
stores your system configuration 
and needs to be re-executed only 
if something changes. 

The two main programs are 
810EGA.EXE and 810CGA.EXE. 
One is used for EGA systems, the 
other for CGA. Both programs 
operate the same way. The EGA 
version supports VGA/EGA 
monitors and has color ca- 
pabilities if your monitor sup- 
ports color. The CGA version has 
reduced graphics resolution and 
the sweep display will be mono- 
chrome. All the photos presented 
here are from the EGA version. 
The CGA version was included 
primarily to support low-end lap- 
top computers using the parallel- 
printer interface. 

When the software is executed, 
a copyright message will be dis- 
played while it is loading the cal- 
ibration files. After a few mo- 
ments the sweep display will 
come up. Figure 11 shows a typ- 
ical sweep display. The display is 



continually updated as the local 
oscillators's (LO's) are swept and 
new data is gathered. The box on 
the left side of the screen con- 
tains the list of function keys 
that are currently active. All user 
interactions from the sweep dis- 
play are initiated by function 
keys, arrow keys, or the ESC key. 
Function key Fl is always used to 
bring up the Instrument Setup 
menu. The user can change all 
the settings of the spectrum ana- 
lyzer from the menu. That will be 
covered in more detail later. 

Function key F10 activates the 
marker function. When the 
marker is on, the sweep is inter- 
rupted until a return to sweep 
mode is commanded (ESC key). 
Once the Marker is up, the user 
can do a peak search, or by using 
function key F7 toggle the delta 
marker on and off. The marker is 
moved using the arrow keys with 
the power and frequency (or delta 
power and delta frequency) dis- 
played in the lower left corner of 
the screen. Another feature of the 
marker is to tune the spectrum 
analyzer as you move it, enabling 
the marker to act as a station in- 
dicator for the FM demodulator. 




FIG. 11— THIS IS WHAT YOU might see on 
a typical sweep display. 

Using an external speaker and an 
antenna on the input you can 
"scan" the bandwidth of the ana- 
lyzer, listening for different FM 
broadcasts. 

Function key F8 activates a 
screen dump. Your printer must 
be selected using SETUP for this 
to work. A large number of 



printers are supported, ranging 
from Laserjets to low-end dot ma- 
trix types. When you return to ac- 
tive sweeping the marker turns 
off and the functions associated 
with it (FM tuning, screen dump, 
and so on) are not accessible to 
you. 

When you're in the sweep 
mode, you can save and recall all 
the settings of the analyzer using 
the function keys preceded by the 
ALT key for saving states, and the 
CNTRL key for recalling states. 
Ten states are available: one for 
each ALT/CNTRL function key 
pair. The states are numbered 
through 9 and are stored on the 
disk as STATEx.DAT STATEO is 
special because it is used as the 
wake up state of the machine. 
You can modify the wake up state 
of the analyzer by just saving a 
new STATEO using the ALT Fl 
keys. 



Instrument setup menu 
By using the up/down arrow 

keys of the setup menu you can 
move to the item you wish to 
change or execute by hitting re- 
turn. Start frequency, center fre- 
quency, and span determine the 
portion of the spectrum ana- 
lyzer's bandwidth you wish to ex- 
amine. Center and start frequen- 
cies cannot be independently 
chosen. In other words, you can 
only specify start and span or 
center and span frequencies. 
That's due to the fixed-span table 
approach used in the analyzer. 
The fixed spans are: 800, 600, 
500, 400, 300, 200. 100, 50, 25, 
12.5, 10,5, 2.5, 1.25, and 0.625 
MHz. When the span is less than 
12.5 MHz, the resolution band- 
width (RBW) is automatically 
switched from 280 kHz to 10 kHz. 
No direct user control is provided 
for the RBW setting. 




THE SOLDER SIDE of the foil pattern is shown here. 




THIS IS THE COMPONENT side of the foil pattern. 



41 




FIG. 12— PARTS PLACEMENT DIAGRAM. Note the location of the four coax runs. Make 
sure you install all chip capacitors first because of their small size. 



to 

o 

z 
o 
cr 
H 
O 

LU 

_l 
LU 

O 

o 
< 
rr 



All resistors are Vb-watt, 5%, unless 
otherwise noted. 

R1, R33— 3300 ohms 

R2, R31, R32, R43— 5600 ohms 

R3-R12, R37, R38, R46, R47, R49. R50, 

R66— 22,000 ohms 
R13, R22, R23, R27, R39, R40, R48, R53, 

R54, R57. R61— 470 ohms 
R14, R56. R60— 1000 ohms 
R15, R28-R30— not used 
R16, R17, R24— 18 ohms 
R18, R45, R59, R62—68 ohms 
R19— 180 ohms, 'A-watt 
R20, R52— 1800 ohms 
R21— 47,000 ohms 
R25— 240 ohms 
R26— 180 ohms 

R34, R35, R51, R55, R58— 56,000 ohms 
R36. R41, R42— 100.000 ohms 
R44, R64— 10,000 ohms 
R63— 390,000 ohms 
R65— 10,000 ohms x 7 SIP resistor 
Capacitors 
C1, C2, C22, C36, C40, C44, C45, C53, 

C56, C63, C64, C91— 1 jjlF, 50 volts, 

tantalum 
C3, C48, C60— 0.1 u.F polyester 
C4, C42, C49. C59— 47,000 pF, polyester 
C5, C6, C9-C18, C32, C46, C47, C61, 

C88-C90— 0.001 (iF, ceramic disc 
C7 T C62— 330 pF, ceramic disc 
C8, C68, C69— 100 pF, ceramic disc 
C19, C38, C66— 22pR ceramic disc 
C20, C26, C34, C37, C41— 10 pF, ceramic 

disc 
C21, C35, C67, C73— 1000 pF, chip 
C23, C71 , C74— 2.7 pF, ceramic disc 
C24, C25, C97— not used 
C27-C31, C33, C50, C70, C72, 

C75-C87, C92-C95— 0.01 (iF, ceramic 

disc 
C39 — 200 pF, ceramic disc 
C43, C51— 0.01 u.F, polyester 
C52, C54 — 1000 pF, polyester 
C55, C57, C99, C10O— 220 jxF, 35 volts, 

electrolytic 
C58— 220 (iF, 16 volts, electrolytic 
C65 — 5 pF, ceramic disc 
C96— 10 iaF, 16 volts, tantalum 
C98— 10 (j.F, 16 volts, tantalum 
Semiconductors 
IC1, IC2— Not used 



PARTS LIST 

IC3— MC34063, step-up voltage reg- 
ulator, Motorola 
IC4, IC5— 74LS244, three-state octal 

driver 
IC6— 74LS04, hex inverter 
IC7-AD558, 8-bit A/D converter, Analog 

Devices 
IC8— 74LS164, 8-bit par out shift register 
ICO, IC10— 74LS374. three-state octal 

driver 
IC11— 74LS32, quad or gate 
IC12— ADC0834, A/D converter, Na- 
tional Semiconductor 
IC13, iC16— NE615, receiver, 

Signetics 
IC14, IC15, IC23— MC44802, PLL, 

Motorola 
IC17— OE-1 75-14, tuner, Zenith 
IC18, IC19—74LS138, decoder 
IC20— 74LS688, address decoder 
IC21— 74LS245, bus transfer 
IC22— LM386, audio amp, National 

Semiconductor 
IC24 — NE602, oscillator/mixer, 

Signetics 
Q1-Q4, Q7— 2N3906, PNP 

transistor 
Q5, G8— MRF9G1, double emitter 

NPN transistor, Motorola 
Q6— 2N3904, NPN transistor 
D1, D4--MV209 or MV2105, varactor 

diode, Motorola 
D2— IN5229B, 4.3 volts, Zener 
D3— 1N4003, diode 
LED1 — Any red light emitting diode 
Other components 
L1— T10307, 0.15 mH, 7-mm can 

type, Toko 
L2— T10407, 1.0 mH, 7-mm can type 

Toko 
L3— 421F224, 5.8 to 3.7 mH, 7-mm 

can type, Mouser 
L4— 220 mH coil, Mouser 
L5— 3 turns of #30 AWG wire on #23 

drill, LS = 0.138" 
L6— 5 turns of #30 AWG wire on #42 

drill, LS = 0.2" 
L7— 3 turns of #30 AWG wire on #42 

drill, LS = 0.138" 
T1— 421F128, 10-mm can type, 

Mouser 



T2— 42IF102, 10-mm can type, 
Mouser 

FL1, FL2, FL5—SKM1, 10.7-MHz ce- 
ramic fitter, Toko or Murata Erie 

FL3, FL4— CFM2-455E, 455-kHz ce- 
ramic filter, Toko 

XTAL1— 34.3000-MHz standard 
crystal 

XTAL2— XTAL107, 4.00-MHZ TTL 
oscillator 

31 — 7-position DIP switch 

Connectors 

J1, J2, J4 — Female F-type bulkhead 
connector 

J3— RCA audio jack, PC board 
mounted (90°) 

J5, Jf3 — F-type connectors are part of 
tuning assemble (IC17) 

J7— 3-pin type, Molex, 0.156" O.C, 
power connector 

P2— 36-pin DIP header 

Two RCA male connectors for coax 
to tuner connection 

Miscellaneous 

• Bottom shield— 3-7/8" x 3-7/8" 
single-sided PC board with glass 
epoxy, copper side facing away 
from board. Four 1 /2-long screws, 
four 4-40 nuts and bolts, four lock 
washers and insulating washers. 

• Lowband shield— 2-1/4" x 2-1/2" 
sheet metal. 

• Rear panel with mounting 
screws. 

• 3 inches of 0.047 rniniture coax. 

• 16 inches of RG174 coax. 

Note: The following items are 
available from DKD Instruments, 
1406 Parkhurst, Simi Valley, CA 
93065; (805) 581-5771: A com- 
plete kit including executable 
and data files on a 5-1/4 inch disk 
with manual, S255.00; Cen- 
tronics interlace cable, $13.00; 
power cable, $4.00; an as- 
sembled, tested, and calibrated 
unit, $500.00. Send check or US 
postal money order. Allow 3 to 5 
weeks lor delivery. California 
residents add 6% sales tax. 



42 



The reference level and at- 
tenuation settings determine the 
power level of the top line of the 
sweep grid. That is a user-entered 
number that can take on any 
floating-point value. The user 
has a choice of three settings for 
internal attenuation: 0, 10, and 
20 dB. The attenuation is imple- 
mented by reducing the gain, not 
by the use of attenuation pads. 
That's a subtle yet significant dif- 
ference from high-end analyzers 
that use switched attenuators for 
gain reduction. User attenuation 
is located in the input path, 
which is convenient for automat- 
ically calculating in the effects of 
inline attenuations. Since that's 
a floating point entry, negative at- 
tenuations (or gains) can also be 
entered in the signal path. There 
are three choices for the vertical 
power scale units using the dB/ 
div entry: 2, 5. and 10 dB. Refer- 
ence level, attenuation, and dB/ 
div affect the placement of the 
power data on the sweep grid. It's 
best to experiment with different 
settings to get a feel for how they 
interact. 

Sweep rate 

The sweep rate determines 
how fast the display is updated 
and how long it takes to go 
through one sweep. It is directly 
affected by the CPU clock speed. 
For a given sweep rate, a faster PC 
will finish the sweep in less time 
than a slower PC. Sweep speed 
increases with higher values of 
sweep rate. The sweep rate and 
power accuracy are interrelated: 
longer sweep times usually result 
in more accurate power measure- 
ments. That has to do with the 
video bandwidth and PLL set- 
tling time. A fixed number of 
sweep rates are provided in the 
analyzer: 1, 3, 5, 10, 15. 20. and 
30. A more complete discussion 
of the sweep rate and power ac- 
curacy relationship is given in 
the README.DOC file. 

Band select 

The band select menu item al- 
lows the user to select which in- 
put is going to be used: highband 
or lowband. The user must select 
the band of operation and con- 
nect to the appropriate input be- 
cause autoswitching is not pro- 
vided. The highband input 
should not be terminated when 
using the lowband input. That 



10.7MHz TO 455kHz 
COAXIAL RUN 



SOLDER SHIELD 

OF COAX TO 
GROUND PLANE 




^C26 



FIG. 13— THE 10.7 MHz TO 455 kHz COAXIAL RUN reduces spurious pickup from the 455- 
kHz IF. 



would result in erroneous power 
measurements. 

The exit to sweep menu item 
returns the user to the sweep dis- 
play. Hitting the ESC key while 
on the menu bar docs the same 
thing. Exit to Dos returns control 
of PC to DOS. 

Calibration 

Three power related calibration 
files are used by the spectrum 
analyzer: one for the automatic 
gain control (AGC), one for the 
received-signal strength indica- 
tor (RSSI), and a user-generated 
error table. The AGC calibration 
tables correct any variations in 
gain using the DAC input to the 
AGC pin of the tuner. Most of the 
variations are in the tuner. One 
table for each value of internal 
attenuation is provided. 

A set of six data files are also used 
for the lowband and highband 
modes: namely the AGC*. DAT files. 
The RSSICAL*.DAT calibration 
files are used to "linearize" 
and map the RSSI voltages to an 
absolute power level. Two 
RSSI files are used; one for 
each RBW. Two user- gene rated 
files, POWERRH.DAT and 
POWERRL.DAT, can be used by 
kit builders to improve the 
accuracy of their power readings 
if they can get their hands 
on the equipment needed. The 
details of using the program 
USERCAL.EXE are covered in 
README.DOC. That error table 
is optional, and for factory cali- 
brated units it is zeroed out. 

If you build a kit, you'll have to 
live with the generic calibration 
files which, as mentioned above, 
result in degraded power ac- 



CHIP CAPACITOR DETAIL 



HOLD CHIP CAP WITH 
TOOTHPICK 




SOLDER 



PC BOARD CONDUCTOR 



FIG.14— USE THIS DIAGRAM asaguideto 
installing the chip capacitors. 

curacy. Most of the power errors 
come from variations in the gain 
of individual tuner modules, 
which are approximately ± 2 to 3 
dB over the entire bandwidth. 
The RSSI data tends to change 
very little. Because of that, the 
largest errors will be at the band- 
switching points. The averaged 
generic calibration files are pro- 
vided with the kit, and are posted 
on the Radio-Electronics bul- 
letin board. 

Construction 

The entire circuit of the spec- 
trum analyzer is mounted on one 
double-sided PC board. We have 
provided foil patterns of the com- 
ponent side and the solder side of 
the PC board if you wish to make 
it yourself. Before mounting any 
components, you should visually 
inspect the board for shorts and 
solder bridges, especially around 
the pads that are surrounded by 
the ground plane. That can be 
done by putting a bright light be- 
hind the board, which really 



m 

H 

m 

DO 



ID 



43 



00 

g 

z 
o 
Be 

h- 
u 

LJ 



Q 
5 

< 



RF INPUT TO TUNER COAX 

TIN 
SHIELD SOLDER TO RCA 

BRAID SHIELD 

FOR SOLDERING 
TO GROUND PLANE R Gl 74 WITH OUTER 

INSULATION REMOVED 




J6 
RCA 
MALE JACK 






TORF 

INPUT 

OF TUNER 



TUNER L0T0PLL1 COAX 



J5 



SOLDER TO RCA 
HCA ^ALE SH , ELD 

JAOK 



TO IC15L0 INPUT 
(C6.PLL1) 



TUNER 
LOOUT 



^m 




ATTACH TO 
GROUND PLANE 



FIG. 15— TWO RG-174 COAX RUNS ARE SHOWN for the RF input to tuner (a) and the tuner 
LO to the PLL1 (o). 



TO T" 
BULKHEAD 
CONNECTOR 
HIGHBAND 

INPUT 



LUWBAND INJECTION COAX 



KEEP EXPOSED 

CENTER CONDUCTOR 

TO A MINIMUM LENGTH 



C66 

22pF 

LOWBAND INJECTION 

OF 145MHZ IF 




SOLDER TINNED SHIELDS TO GROUND PLANE 



FIG. 16— THE RF FEED FOR the lowband injection coax. Make sure your center conductor 
is as short as possible. 



makes the pads standout. After 
careful visual inspection, check 
the +5-, +12-, and +33.3-volt 
power buses for shorts to 
ground. 

Figure 12 shows the compo- 
nent placement, as well as the lo- 
cations for all coax runs. Before 
mounting any components, a 
short coax run must be installed 
on the top side of the board. A 
small piece of semirigid coax is 
used to connect the 10.7-MHz IF 
from FL5 to the input from the 
455-kHz IF mixer (IC13, pin 1). 
The coax reduces the spurious 
pickup for the 455-kHz IF. Cut, 
strip, and bend the coax as 



shown in Fig. 13. Using an ohm- 
meter, check to make sure the in- 
ner conductor is not shorted to 
ground. RG174 type coax, with 
the external insulation removed, 
can be used but it's a tight fit. 

You're now ready to start sol- 
dering in the components. Install 
chip capacitors C21, C35. C67. 
C72. and C73 first, using Fig. 14 
as a guide. Because of their small 
size they can be very difficult to 
install with the board fully stuff- 
ed. Solder in all remaining capac- 
itors. Check them off on the parts 
list as you install them, then re- 
check the power buses with an 
ohm meter. You should read infi- 



nite resistance, as before. If you 
read a short or very low resis- 
tance, look for solder bridges. 

Now solder in the resistors ac- 
cording to the component layout. 
Again, check the power buses for 
shorts using the ohmmeter. In- 
stall the inductors and coils next. 
Ifyoubuyakit, L5, L6, and L7 are 
already made. Install all filters 
and crystals. Their leads can go 
in either direction. Lay XTAL1 
down flat and solder its case to 
ground. The case of XTAL2 
should also be tied to ground 
using a small piece of wire. Sol- 
der in the diodes, being careful to 
observe the correct polarity. Do 
the same for transistors QI-Q8. 
Q5 and Q8 are surface-mount 
types from Motorola; "M" marked 
on the top indicates the collector. 
Using the ohmmeter again, 
check for shorts on the power 
buses. 

When installing the IC's, use 
sockets for all the chips except 
the NE615's, MC44802s, and the 
NE602. Those chips need a close 
connection to the ground plane 
to ensure proper operation. 
Check for shorts again. After you 
install IC3 (the MC34063 step-up 
voltage regulator), make sure you 
have 33.3 volts DC between R62 
and ground. That is where the 
33.3-volt power line comes from. 
If you really want to be thorough, 
use an ohmmeter to check every 
IC pin for shorts to ground and 
verify that the pins that should 
be grounded are grounded. Now 
install the mechanical parts: the 
RCA jack, 3 -pin Molex connector, 
36-pin dual header (for the paral- 
lel interface), DIP switch SI, and 
R64. 

Tuner installation 

Before the tuner can be in- 
stalled, two RG-174 coax runs to 
the RF input and the LO output 
must be connected, as shown in 
Figs. 15-a and -b. If you don't get 
the lowband option, the RF input 
is just a direct feed using RG59 
cable to a female/female F-type 
connector on the rear panel plate. 
After the cables are made, con- 
nect the LO cable to the board 
and solder the coax shield to the 
ground plane. Now make the RF 
feed. (If you have the lowband op- 
tion. Fig. 16 shows you how to 
connect the coaxial cable to the 
board.) 

Using the outer shield of the 



44 



lowband coax as a gauge, put the 
tuner on the board, top side up, 
by tacking the corners down with 
solder. Don't solder the lowband 
shield on yet, that goes on after 
tuning L6. Two holes are pro- 
vided for using tie wraps to hold 
down the tuner if you desire. Cut 
small pieces of wire to connect 
tuner pins 1—8 on the bottom 
edge to the appropriate holes on 
the board. Make sure the if out 
jumper is as short as possible. 
Now connect the two RCA jacks 
for the lo out and the rf in coax 
runs. 

Terminal panel and shield 

Before you mount the terminal 
panel to the board, connect the 
highband coax run as shown in 
Fig. 17. Connect the coax to the 
board first, then connect the low- 
band and comb F connectors to 
the terminal panel. Now connect 
the highband F connector to the 
terminal panel and secure the 
panel to the board using two 4-40 
screws and nuts. Solder jumpers 
from the plated holes in the 
printed-circuit board to the cen- 
ter conductor lowband and comb 
F connectors. 

Figure 18 shows the mounting 
details of the bottom shield, 
which is made of a single-sided 
PC board and is mounted, with 
the copper side facing away from 
the main board, using four 4-40 
bolts. This shield should be in 
place before you perform any 
final tuning as it effects signal 
levels. 

Coil pretune 

We're almost ready to power the 
unit up, but first we need to pre- 
tune the coils. Most of coil adjust- 
ments are noncritical. Use the 
following initial settings just to 
get you started: 

• LI — Slug is Wi turns from the 
bottom (fine adjust later). 

• L2 — Slug is l'/2 turns from the 
top ( ± 1 turn). 

• L3 — Slug is all the way to the 
bottom. 

• L5 — Close wound. 

• L6 — Close wound. 

• L7 — Close wound. 

• Tl — Slug is IV2 turns from the 
top, 

• T2-^Slug is I'/a turns from the 
top. 

The spectrum analyzer should 
work with those settings. All ad- 
justments from here on for fine 
tuning. 



HIGHBAND COAX TO REAR PANEL 



TIN SHIELD AND 
HERE SOLDER TO 'TCONNECTOR 



J1 

HIGHBAND 

INPUT 

"PJACK 



RG174 

OUTER INSULATION 

REMOVED 



TIN SHIELD 
AND SOLDER TO 
GROUND PLANE 



NUT 




REAR PANEL 



SOLDER TO CENTER CONDUCTOR OF BULKHEAD JACK 



FIG. 17— THE HIGHBAND COAX RUN is shown here. This coax connection must be made 
before the terminal panel is installed on the PC board. 



BOTTOM SHIELD 



4-40 BOLTS (4) 
Vi" LONG 



TUNER 




COPPER SIDE 

SINGLE SIDED (3 7 /«"x3 7 /s") 
GLASS-EPOXY BOARD 
COPPER SIDE DOWN 

INSULATING 

4-40 NUT--" \ WASHER 

4-40 NUT 

FIG. 18— THE BOTTOM SHIELD ASSEMBLY is shown here. Make sure the copper side of 
the shield is installed away from the PC board. 



First power up 

Put the card in the computer 
or, for external use, connect it to a 
parallel port and external power 
supply. Connect the comb output 
to the highband input and turn it 
on. Check the +5-, +12-, and 
+ 33-volt levels to make sure they 
are correct. Run either 810EGA 
or 810CGA program, depending 
on your video adapter. The sup- 
plied wake-up state is a span of 
400 MHz with a start frequency 
of 100 MHz. Assuming every- 



thing goes well, you should see a 
series of lines 4 MHz apart slowly 
rolling off in amplitude. If you 
don't, go to the "Troubleshoot- 
ing" section. 

Tuning the unit 

The spectrum analyzer can be 
used to fine tune LI, L6, Tl. and 
T2; L2. L3. L5, and L7 should 
need no further adjustment. Ad- 
justing the coils is easier with the 
card outside of the PC case, for 
instance if you use the parallel 



0) 

m 

| 

m 

c 
r- 

to 
tc 



45 



LOWBAND SHIELD 
-2Vz" 



10 
O 

Z 

o 
BE 
P 

o 
in 

_i 
iij 

o 

Q 

< 

en 




BEND OVER AT 

DOTTED LINES INTO V" 

SHAPE 

FIG. 19— THE LOWBAND SHIELD is sol- 
dered on the top side of the PC board. 



CORRECTIONS 
There may have been some con- 
fusion where the DAC output from 
IC7 {Fig. 10) goes to from our Part I 
article. Just to clarify those con- 
nections, we have redrawn the 
correct DAC outputs in Fig. 20. 
Two other corrections are noted 
below. 

• The power-supply line to Pin 2 of 
IC15, IC23, and IC14 is 33.3 volts 
DC. 

• Two signal labels, LO JN and 
v tune' should be reversed in IC23 
or the signal-processing block di- 
agram (Fig. 6). 



+ 12V 




FIG. 20— THE DAC OUTPUT from IC7 goes 
to IC17 and IC12 as shown here. 

interface. Allow about 5 minutes 
for warm up and then tune the 
coils in the following sequence. 
The maximum span available 
from the lowband is affected by 
L6. It is tuned by spreading, or 
closing, its turns. Connect the 



comb out to the lowband input 
and set the spectrum analyzer as 
follows: 

• Bandselect — lowband 

• Span— 100 MHz 

• Start freq— 5 MHz 

• Inter atten— 10 dB 

• Ref level 40 dBm 

The sweep display should show 
lines every 4 MHz. If the upper 
end lines are missing, open up L6 
a little and the upper lines should 
start appearing. You should be 
able to see the line at 104 MHz 
when L6 is adjusted properly. 
Once L6 is adjusted and you're 
confident that the lowband cir- 
cuit is working properly, install 
the shield over the circuit. Figure 
19 shows the details of that 
shield. 

Set LI by observing the power 
level of the noise floor. Terminate 
the highband input in 50 to 75 
ohms and set the band select to 
highband. Use the following set- 
tings to make a measurement: 

• Span— 12.5 MHz 

• Center frequency — 120 MHz 

• Sweep rate — 3 

• Inter, atten— 10 dB 

• Ref level— -40 dBm 

The sweep display should show 
almost a flat line. Turn the slug of 
LI until the noise floor reads 
-100 dBm. An alternative and 
more accurate method requires a 
crystal source of known power 
level. For best results, the fre- 
quency of the source should be 
between 100 to 500 MHz. Set the 
spectrum analyzer to display 
your line using the 12.5-MHz 
span and a sweep rate of 1. Now 
adjust LI so that the power level 
of your line is correct. 

Tl is tuned by using the spec- 
trum analyzer as an FM radio. 
The setup settings are: 

• Span— 25 MHz 

• Start freq— 85 MHz 

• Band select — highband 

• Volume potentiometer (R64) — 
centered 

Connect an antenna up to the 
highband input. You may have to 
use an outside antenna. You can 
make a simple antenna by at- 
taching a 2- to 3-foot piece of wire 
to the center conductor of the in- 
put. Connect a speaker to the au- 
dio out RCA jack. Now let the 
analyzer make a few sweeps. You 
should be able to hear FM broad- 
casts as the analyzer sweeps by 
them. Now activate the marker 
and find a strong station. Put the 



marker at the peak of the signal, 
even if the audio drops out. Ad- 
just Tl now for the best sound. 
T2 can be adjusted the same way, 
but you'll have to pick off the au- 
dio and amplify it as it is not con- 
nected to an amplifier. You will 
also need a narrowband FM 
broadcast for proper adjustment. 
With a little hunting you should 
be able to find one. (Try your local 
National Weather Service broad- 
cast station in the 162.4-162.6 
MHz band.) The adjustments of 
Tl and T2 only effect the FM de- 
modulation and do not effect the 
accuracy of the instrument. 

Troubleshooting 

Typical symptoms indicating a 
problem are a flat or "pegged" 
sweep display and no response to 
inputs. Two programs are avail- 
able to help in the troubleshoot- 
ing process; BLINK.EXE and 
ADCDAC.EXE. BLINK is used to 
give a simple visual indication 
that the host PC has some com- 
munication with the card. With 
the card plugged into the PC or 
parallel cable, run BLINK, The 
LED on the card should blink at 
approximately 1-second inter- 
vals. If no blinking at all occurs, 
you have a communication prob- 
lem with the PC. Double check 
the interface settings using SET- 
UP; if those are wrong the card 
won't respond. If wiggling cables, 
checking power-supply voltages, 
and every permutation of inter- 
face selections does not result in 
a successful BLINK, you most 
likely have a hardware problem. 

ADCDAC.EXE is a more exten- 
sive test in that both reading and 
writing to the card are involved. 
There is little chance that this 
test will be successful if BLINK 
fails. ADCDAC sends a voltage 
level to the DAC, then reads that 
voltage using the ADC. If the read 
voltages are within the toler- 
ances, the test is declared a suc- 
cess. ADCDAC returns a pass/fail 
verdict upon completion. If you 
fail, it could be an interface prob- 
lem or a problem with the ADC or 
DAC. Passing does not guarantee 
that all systems are go, just that 
the interface and ADC/DAC seem 
to be working. 

If you still can't find the prob- 
lem, see README.DOC for more 
things to try, or call DKD Instru- 
ments at (805) 581-5771. They'll 
be happy to help you. R-E 



46 



DAVID T. MIGA, CET 



t*« _ ES,GW »*C Wt(Jrs e 

<"0d e __. c _ 6DS-76 „.. 

J * • • •* 

cap ^ Nef» Pch 

IW VOLTS - HL,^ HV 



c 



BUILD THE 




MICROANALYZER 



Repair microwave ovens the easy way 
with the Microanalyzer. 



DID YOU KNOW THAT MICROWAVE 

ovens were invented more than a 
quarter century ago using tech- 
nology more than half a century 
old? Even so. many electronic 
technicians are reluctant to ser- 
vice them because they do not 
understand them. That's a 
shame, considering the fact that 
there are millions of them in use. 
True, there is enough power in 
even the smallest microwave 
oven's power supply to kill a per- 
son, yet most technicians repair 
television receivers with many 
times more voltage without giv- 
ing it another thought. The point 
is that a technician with the 
proper knowledge, who follows 
safe, intelligent procedures will 
never have a bad experience, and 
can make lots of money. This arti- 
cle explains how microwave 
ovens work, and shows you how 
to check all of the critical parts 
using the Microanalyzer project 
that we'll show you how to build. 

How they work 

A microwave oven is similar to 



been purposely tuned to be un- 
stable, and therefore to oscillate. 

The oscillator/amplifier tube is 
called a magnetron, and its sche- 
matic is similar to an ordinary 
tube rectifier (see Fig, 1). How- 
ever, instead of the electrons hav- 
ing free space to boil off of the 
filament/cathode to be grabbed 
by the plate, the electrons are 
purposely frustrated by placing a 
powerful circular magnet around 
the cathode, causing the elec- 
trons to rotate around the cath- 
ode on their way to the plate. 
There are cavities in this section 
of a critical diameter that will 
cause the oscillations to be of a 
certain frequency, usually 2450 
MHz, Because the plate of the 
tube does not operate at a high 
voltage, but instead is at ground 
potential, the cathode, therefore, 
is powered by a very high nega- 
tive voltage, usually between 
three and four thousand volts. 
The filament of the tube is di- 
rectly heated, so it must be capa- 
ble of handling the high negative 
voltage as well as passing a 3 -volt 
AC filament current of about 10 



amps. In most microwave ovens 
a single power transformer has 
both high -voltage and low- volt- 
age secondaries. 

The magnetron tube has a wire 
in the plate cavity that intercepts 
the swirling electrons and passes 
the energy to the top of the tube 
where the energy is transmitted 
by a small antenna timed to the 
proper wavelength. The energy 
therefore transmits horizontally, 
similar to the ripples in a pond 
caused by a dropped pebble. The 
microwaves are routed by a 
square metal tube, or duct, called 
a waveguide, whose cross dimen- 
sions are tuned to the same wave- 
length as the magnetron. The 
waveguide directs the micro- 
waves to the inside of the oven 
through a plastic or mica panel 
called a waveguide cover. The 
cover keeps food panicles, 
grease, and steam from entering 
the waveguide, yet passes the 
magnetic energy. 

Most microwave ovens have a 
stirrer, which can be motor acti- 
vated, or in many ovens may be 
blown propeller style by the air 



»nc 






CO 

m 
u 

S 

03 

m 

ID 



47 



forced through the cooling fins of 
the magnetron. The stirrer is in 
the top of the oven, and it reflects 
the microwaves all around the 
oven cavity. 

All microwave ovens have safe- 
ty features to prevent unsafe mi- 
crowave emissions. A series of 
micro-switches operate in a cer- 
tain sequence, and are in series 
with one or more thermal switch- 
es, so as to assure that the power 
supply will operate only when all 
of the switches are in their cor- 
rect positions. There's even a 
switch designed to short out the 
AC line, blowing the fuse, if any 
of the switches malfunction (see 
Fig. 2). 

In operation, a mechanical 
timer or an electronic control 
unit will cause a relay or triac to 
pass 120-volts AC to the primary 
of the power transformer. The 
transformer has a 3-voit second- 
ary for heating the magnetrons 
filament, and a 1500- to 2500- 
volt secondary for the high-volt- 
age power supply. To keep the 
windings count low, a voltage- 
doubler circuit is used (see Fig. 
3). During one half of the 60-cycle 
current, the transformer charges 
a high-voltage capacitor to 
ground through a high- voltage 
diode, cathode to ground. When 
the polarity reverses, the capaci- 
tor is free to discharge through 
the high-voltage winding. Since 
the voltages are in series, the 
voltage is doubled, although the 
current is reduced to what the 
capacitor can supply during its 
discharge. Therefore, the size of 
the capacitor controls the wat- 
tage, and the magnetron actually 
transmits energy in 60-Hz 
pulses. Note that the capacitor 
may remain charged for hours 
after using the oven, so it must 
be properly discharged before 
any components in the oven are 
checked. 

When a microwave oven is op- 
erated, the magnetron usually 
takes about 3 seconds to fire up, 
because the filament must come 
up to temperature. If one listens, 
the firing up is audible: the mag- 
netron emits a 1-second buzz im- 
o mediately after the filament heats 
g up. In most ovens with several 
oc power settings, the actual power 
o delivered to the magnetron does 
jjj not vary, but instead is cycled on 
o and off by the controlling circuit- 
Q ry. The fan and light stay on, but 
en the primary of the power trans- 



en 




FIG. 1— A MICROWAVE OVEN'S oscillator/amplifier tube is called a magnetron. The 
electrons are purposely frustrated by placing a powerful circular magnet around the 
cathode, causing the electrons to rotate around the cathode on their way to the plate. 
There are cavities in this section ot a critical diameter that will cause the oscillations to be 
of a certain frequency, usually 2450 MHz. 



former is energized or de-ener- 
gized by a relay or triac, as shown 
in Fig. 4. 

More sophisticated ovens may 
use a temperature probe, or even 
a heated tin-oxide gas-vapor sen- 
sor to determine when the food is 
cooked. The thermistor's resis- 
tance in the probe, or the voltage 
output of the gas sensor, is 
routed to a microprocessor, 
which has been programmed 
with the proper values to turn off 
power when the food is fully 
cooked, or "smells" done. 

The Microanalyzer 

The Microanalyzer is actually 
several pieces of test equipment 
rolled into one easy-to-carry cab- 



inet. First, a 3 '/a digit DVM is in- 
corporated to measure up to 500- 
volts AC or DC, with a high-volt- 
age input that allows up to 5000- 
volts AC or DC. Second, a high- 
voltage supply is wired to a cir- 
cuit that allows the testing in-cir- 
cuit of the high- voltage diode and 
capacitor, with test voltages as 
high as 700 volts peak-to-peak. 
The results are plainly displayed 
by four neon indicators. Third, a 
semiconductor checker allows 
the testing of devices such as tri- 
acs, silicon controlled rectifiers, 
bipolar transistors, diodes, and 
MOSFETs. 

Figure 5 is the schematic of the 
Microanalyzer. Power trans- 
former Tl has a low-voltage sec- 



48 



120 VAC 



DOOR 
INTERLOCK 
SWITCH #1 



/fTX MAGNETRON 
THERMAL 
SWITCH 







DOOR LATCH 
SWITCH 



I 



TO PRIMARY OF POWER TRANSFORMER 



FIG. 2— ALL MICROWAVE OVENS have 
safety features to prevent harmful emis- 
sions. A series of micro-switches and 
thermal switches assure that the power 
supply will operate only when all of the 
switches are in their correct positions. 



ondary that provides power to the 
DVM chip, IC2, via diode bridge 
BR1 and regulator IC1. as well as 
AC power to the semiconductor 
tester. The high-voltage second- 
ary provides 250-volts AC for the 
high-voltage diode and capacitor 
tester. A small sample voltage is 
taken from the secondary's cen- 
ter tap via R30, D12. and D9 for 
the negative voltage required by 
IC2. 

Selection between the DVM, 
the capacitor tester, and the di- 
ode tester is done by three-pole, 
three-position switch S2, In the 
"capacitor- test" and "diode- test" 
positions, one pole of S2 con- 
nects the internal high-voltage 
source to banana jack J2 ; a sec- 
ond pole turns off the DVM dis- 
play via D8, R25. and Q3; the 
third pole selects either high- 
voltage AC for testing diodes, or 
DC for testing capacitors. If the 
selector is placed in the "diode- 
test" position, a 250-volt RMS po- 
tential is placed through current- 
limiter Rl to the diode under test 
between Jl and J2. 

Across Rl is neon-indicator 
NE3. which will light only if the 
AC current flow is in the wrong 
direction; if the diode is shorted, 
for example. Diode D5 will keep 
NE3 off if the diode under test is 
good. The diode-OKneon indica- 
tor (NE1 ) will illuminate only with 
DC, since AC will be bypassed 
across NE1 by CI and C2. The 




FIG. 3— TO KEEP THE POWER TRANSFORMER'S windings count low, a voltage-doubler 
circuit is used to generate high voltages. 



MAGfJtTRON 




INTERLOCK 
SWITCHFS 



1 20 VAC 



LOW-VOLTAGE 
POWER SUPPLY 




HIGH VOLTAGE 
POWER SUPPLY 




^ CONTROL 



FIG. 4— IN OVENS WITH SEVERAL POWER SETTINGS, the magnetron is cycled on and 
off by the controlling circuitry. The fan and light stay on, but the primary of the power 
transformer is energized or de-energized by a relay or triac. 



diode-open neon indicator (NE2) 
cannot light if the diode under 
test is good, since the diode will 
keep the positive voltage across 
R5, D6, and NE2 under 8 volts, 
which is the forward-bias poten- 
tial of a good high- voltage diode. 
Diode D6 will keep NE2 off dur- 
ing negative flow; however, if the 
diode under test is open, there is 
sufficient positive voltage to light 
NE2. 

Flipping S2 to the "cap-test" 
position switches Dl in line 
which causes a pulsating nega- 
tive DC voltage to appear across 
Rl. With an open circuit, NE1 
and NE3 will be off because there 
is insufficient voltage across Rl 
to illuminate either one. Indica- 
tor NE2 will be off because only a 
positive voltage can light it, and 
NE4 will be off because the 250- 
volt DC signal is not high enough 
to break down the reverse junc- 
tions of diodes D3 and D4 in se- 
ries with NE4 and R2. 



If the capacitor under test is 
0. 1 p-For higher, the negative cur- 
rent flow will charge it through 
Dl; however, when the current 
flow reverts to positive, Dl blocks 
the flow, which now is the com- 
bined voltage of Tl's secondary in 
series with the charged capaci- 
tor. The combined voltage is now 
enough to break down the re- 
versed junctions of D3 and D4, 
protected by current-lirniter R2, 
and NE4 glows . A val ue below . 1 
p\F will create a voltage lower than 
NE4 usually requires to conduct, 
so C14 is placed across NE4 to 
charge up to NE4's ionization 
point. Because of that, any ca- 
pacitor that is below the normal 
value found in most microwave 
ovens will cause the NE4 to flash, 
due to the relaxation oscillator 
circuit. Capacitor values of 0.5 
H-F or higher will illuminate NE4 
continuously, while smaller and 
smaller values will cause NE4 to 
flash slower and slower. 



49 




50 



FIG. 5 — POWER TRANSFORMER T1 has a low-voltage secondary thai provides power for 
the Microanalyzer's circuitry. The high- voltage secondary provides 250- volts AC for the 
high-voltage diode and capacitor tester. 



TO 

S2-b 

COMMON 

(FIG.7) 




FIG. 6— ALL COMPONENTS ON THE MAIN BOARD are mounted on the component side 
except (or R32 and R33 which must be tack-soldered to the solder side of the board. 



One quirk of this circuit is that 
if the capacitor under test is 
shorted, not only will short-in- 
dicator NE3 glow, but so will NE1, 
the diode-OK indicator. Since a 
capacitor is under test here, the 
user can simply ignore the diode- 
OK lamp. If that is bothersome to 
the user, a 4-pole switch may be 
used for S2, with the fourth pole 
used to switch in NE1 in the "di- 
ode-test" position only 

The voltmeter circuit uses the 
popular 7107 DVM chip (IC2). 
The AC/DC switch (S3) switches 
D7 in or out so that IC2 always 
sees either positive or negative 
voltage, but never AC. Because 
the single diode is a half-wave 
rectifier, normally the reading 
will be only a small portion of the 
true RMS voltage; therefore, a 
second pole of S3 switches from 
R23 to a trimmer, R34, so that 
the meter can be adjusted to read 
the correct RMS voltage in the 
"AC" position. Because IC2 uses 
an on-board oscillator for the 
dual-slope integrating analog- to- 



digital converter, trimmer-capac- 
itor C13 has been added across 
C8 so that the sampling frequen- 
cy can be varied. If the trimmer 
capacitor is left out, any AC volt- 
age readings may be unstable; 
therefore, the chip's sampling 
frequency can be adjusted to an 
exact multiple of the 60-Hz AC 
voltage to be measured. 

Trimmer R35 is the basic refer- 
ence-voltage adjustment used to 
calibrate the DVM on the lower 
scale DC measurement. The val- 
ues of R7 and R23 or R34 will 
correctly divide the input voltage 
up to 500 volts AC or DC down to 
2 volts for the DVM chip (IC2). 
but if anything up to 5000 volts 
must be measured, the voltage is 
passed through banana-jack J2 
which uses R8— R15 for an addi- 
tional 43 megohms to reduce the 
voltage to a compatible level. 

The circuit containing Ql and 
Q2 constantly measures the volt- 
age at J2. If any AC or DC voltage 
appears at J2, one or both tran- 
sistors are biased to turn on the 



decimal-point LED in the display. 
Stereo phono-jack J4 is used 
for testing semiconductors. A 
matching phono plug, PL1, with 
a black lead on the outer conduc- 
tor, a red lead on the middle con- 
ductor, and a yellow lead on the 
tip conductor, plugs into J4 and 
provides test clips to attach to 
components. The 5-volt AC 
source from Tl is passed through 
LED1 and LED2 through cur- 
rent-limiter R16. Both LED's will 
remain off when the test leads at 
J4 remain unconnected, but 
both will illuminate when the red 
and black leads are shorted. To 
test a semiconductor, connect 
the red lead to the collector of a 
transistor, the anode of an SCR, 
MT2 of a Iriac, or the drain of a 
MOSFET; connect the black lead 
to a transistor emitter, SCR cath- 
ode, triac MT1. or MOSFET 
source; and connect the yellow 
lead to a transistor base or gate of 
any other part. Pushing test but- 
ton S4 will forward-bias the de- 
vice and, depending on whether 
either, both, or neither LED 
lights, a semiconductor device 
can be tested for proper con- 
ductance. More details on the 
testing will be given later. 



en 
m 



IX 

m 

33 



51 



u 
z 

o 

IX 

F 
o 



UJ 

6 

D 
< 




DIODE 



FIG. 7— MOUNT THE PARTS ON THE DISPLAY BOARD as shown here. Note that R6 and 
C14 are soldered to the back of th,e board. 



Construction 

The Microanalyzer consists of 
two single-sided PC boards: a 
main board containing the 
power supply and the DVM chip 
with auto decimal -point circuit- 
ry, and a display board con- 
taining the indicators, displays, 
switches, and test jacks. The dis- 
play board is joined to the front of 
the main board by soldering in- 
terconnecting foils at their edges. 
We've provided the foi! patterns 
in case you'd like to make your 
own boards. Alternatively, the 
boards, as well as complete kits, 
are available from the source 
mentioned in the parts list. 

Almost all components, except 
the power transformer and 
switches SI and S5, are mounted 
on the PC boards. Follow the 
parts layouts for the main and 
display boards. Figs. 6 and 7, re- 
spectively. Solder all jumpers on 
both boards first, followed by the 
fuse, resistors, trimmers, diodes, 
capacitors, transistors, regulator 
[CI, and sockets for the 7-seg- 
ment displays and IC2, in that 
order; do not put IC2 in its socket 
just yet. Prepare switches S2-S4 
by soldering 1-inch lengths of sol- 



id wire to the terminals to make 
them PC-mountable. Do not put 
too much solder on S2 or else it 
may not fit between the display 
board and front panel. 

Mount, but do not solder the 
neons, LED's, and prepared 
switches in the display board. In- 
sert the digital displays in their 
sockets. As indicated by the 
dashed lines in the parts-place- 
ment diagrams, tack-solder R32 
and R33 to the back (the solder 
side) of the main board, and R6 
and C 14 to the back of the display 
board. Hold the display board in 
position next to the main board 
using the slots and bosses in 
bothboards, and solder all of the 
foil connections, making sure 
that the boards are exactly per- 
pendicular. Check all connec- 
tions for solder bridges. 

Solder the power-transformer 
wires to the main board, and sol- 
der three 4-inch wires in the 
holes marked for both switches 
SI and S5. If you are using an 
illuminated switch for S5, install 
6-inch wires in the holes marked 
LED3. Solder the power switch 
(SI) to its wires. 

Assuming you have purchased 



a ready-made front panel and 
case {see the parts list), you can 
mount all of the jacks and indica- 
tor lenses on the front panel just 
like the prototype, and slip four 
5 /s-inch heat-shrink tubes over 
the neons. Otherwise you can 
make your own front panel in a 
similar fas ion. Remove all hard- 
ware from S2— S4, but leave one 
nut on S3. Mount the front panel 
and the PC-board assembly in 
the bottom shell of the cabinet. 
The neons, LED's. and switches 
can now be extended to reach the 
panel to be mounted. Adjust the 
nut on S3 to match the shaft 
length of S2, and install and 
tighten the remaining hardware 
for all three switches. Solder the 
components after they have been 
mounted. Also mount SI and S5 
in the panel and wire them up; 
note that the other side of S5 is 
connected to the rear of the dis- 
play board on the center contact 
of S2 (S2-b common). 

Remove the assembly from the 
cabinet, turn it over, and wire up 
jacks Jl— J4 to the holes marked 
on the display board using the 
shortest possible lengths of very 
thin solid wire. Remember to 
wire the LED3 wires to the in- 
dicator inside S5 only if a 5-volt 
bulb or LED is installed: the in- 
dicator will light only when the 



52 



PARTS LIST 



All resistors are '-i-watt, 5%, un- 
less otherwise Indicated. 

R1— 10,000 ohms 

R2— 47,000 Ohms 

R3, R5— 22,000 ohms 

R4— 39,000 ohms 

R6, R17— 220 ohms 

R7, R11, R19-R22, R36— 10 
megohms 

R8-R10, R12-R15, R18— 4,7 
megohms 

R16— 150 ohms 

R23— 10,000 ohms 

R24 — 1 megohm 

R25— 2200 ohms 

R26— 25,000 ohms, metal, 1% 

R27— 5600 ohms 

R28— 100,000 ohms 

R29 — 470,000 ohms 

R30— 68,000 ohms 

R31 — 120 ohms (optional for illumi- 
nated S5, see text) 

R32, R33 — 180.000 ohms 

R34— 50.000 ohms, 10-turn trimmer 

R35— 1000 ohms, 10-turn trimmer 

Capacitors 

C1, C2— 0.47 ^F, 350 volts, 
electrolytic 

C3 — 47 h,F, 16 volts, electrolytic 

C4 — 1000 p.f, 25 volts, electrolytic 

C5— 220 jjlR 16 volts, electrolytic 



C6, C7— 0.47 |iF, 100 volts. Mylar 
C8— 100 pF, polystyrene 
C9— 0.1 n.F, 100 volts, Mylar 
C10— 0.01 |j.F, 100 volts, Mylar 
C1 1—0.047 (i.F, 100 volts, Myiar 
C12— 0.22 m-F, 100 volts, Mylar 
C13 — 30 pF, ceramic micro trimmer 
C14— 0,47 nR 200 volts, Mylar 
C15— 120 pF, 500 volts, silver mica 
Semiconductors 
IC1— 7805 5- volt regulator 
IC2— ICL7107CPL 3Vfcdigii DVM 

chip 
D1, D2, D5-D7, D12— 1N4007 diode 
D3, D4, D8— 1N4148 diode 
D9-D11— 1N4733 5-volt Zener diode 
BR1— ECG5304 400-PIV 1.5-amp 

bridge rectifier 
Q1, Q3— 2SA733PNP transistor 
Q2— 2SC945 NPN transistor 
LED1. LED2 — orange light-emitting 

diode 
LED3 — light-emitting diode or 5-vo!t 
lamp (optional for illuminated S5) 
DSP1-DSP4— MAN 4710A com- 
mon-anode 7-segment LED 
display 
Other components 
S1— SPST pushbutton switch 
S2— 3PDT CO. switch 
S3— DPDT switch 



S4— SPST pushbutton switch 
S5 — SPST pushbutton switch (illumi- 
nated optional) 
T1— 120 VAC primary, 250 VAC C.T 
25 mA secondary, 6 VAC, 1 amp 
secondary 
J1 , J2 — red banana jack, '/s-inch 
J3 — black banana jack, '/2-inch 
J4 — stereo mini phono jack 
PL1 — stereo mini phono plug 
F1— 1A, 250V pigtail fuse, Littlefuse 

318.500 
NE1-NE4 — NE-2H neon indicators 
Miscellaneous: Amerex 570 black 
cabinet, hardware, AC line cord, 
3.5mm lamp lenses, wire, solder, 
etc. 

Note: The following parts are avail- 
able from EDS, Inc., 275 Rock Is- 
land Road, N. Lauderdale, FL 
33068: Set of drilled and 
screened main and display PC 
boards for $25; kit of all parts 
and boards for S199; complete 
kit including Amerex cabinet 
with screened and machined 
front panel for $249. Please in- 
clude $4 shipping for boards 
only, or $8 for kits. Florida resi- 
dents must include 6% sales tax. 



diode or capacitor functions are 
selected, while the digital display 
will illuminate only when the se- 
lector is in the "volt" position. 
Mount transformer Tl to the cen- 
ter floor of the cabinet using #8 
bolts and nuts. Run the AC line- 
cord through the hole in the back 
of the cabinet and solder the 
leads to the main board. Install 
the line-cord strain relief: you 
may have to melt it to the inside 
of the cabinet for added strength. 
Finally, mount the assembly to 
the bottom shell of the cabinet 
and proceed with making of the 
test leads. Figure 8 shows the in- 
side of the completed unit. 

Because the unit will be used to 
measure potentials up to 5000 
volts, it is important to use wire 
intended for use as test leads, 
such as the rubber-insulated va- 
riety. Solder fully insulated ba- 
nana plugs to one end of the 
wires, and fully insulated al- 
ligator clips to the other end. The 
semiconductor test wire is made 
from an ordinary piece of 4-con- 
ductor telephone wire, with only 
the red, black, and yellow wires 
used. Solder a 3,5-mm stereo 
phono plug (PL1) to one end. 



being sure that the pin-out 
matches the jack ( J4), and solder 
small IC clips or micro alligator 
clips to the remaining end. 

After you have checked for sol- 
der bridges, bad connections, 
and proper component polarities 
and values, you can apply power. 
Measure the voltage at the 
positive terminal of C5; it should 
be +5-volts DC measured to 
ground. The anode of D9 should 
measure — 5-volts DC, and the 
S5 pad on the main board should 
be 250-volts AC. If the voltages 
appear to be normal, turn off 
power and install IC2 in its sock- 
et. Turn on power and cycle S2 to 
be sure that the digital display 
and LED3 work properly. If every- 
thing looks good, plug in the 
high- voltage test leads and put 
S2 in the "diode test" position. 
Press S5 and verify that NE2 
(open diode) illuminates. Short 
the test leads and press S5 again 
to see that NE3 (short) lights. 
Now. connect a high- voltage test 
diode with red at anode and black 
at cathode, and check that NE1 
(diode OK) lights. Note that if the 
diode is connected backwards, 
all three diode- test lamps will il- 



luminate simultaneously. 

Check the capacitor- test func- 
tions with high-voltage capaci- 
tors rated between 0.01 and 1.0 
jiF and verify the correct func- 
tions of NE3 and NE4. Re- 
member that voltages across the 
test leads can be as high as 700 
volts p-p when S5 is pressed, so 
please be careful. Since the test 
voltages are fully isolated from 
the power line, and one hand is 
needed to push the test button, it 
would require a three-handed 
person to get a shock, but the 
warning is given anyway. 

Next check the semiconductor 
tester. Plug in the 3-conductor 
test cord and connect the ends to 
an NPN transistor using red for 
the collector, yellow for the base. 
and black for the emitter. With- 
out pressing S4, LED2 may be 
dark or slightly lit. That is nor- 
mal reverse leakage for an NPN 
transistor, and will be brighter 
when testing low-voltage, high- en 
frequency transistors. Pushing -v 
S4 will darken LED2 and brightly | 
illuminate LED1, showing trans- w 
conductance. Testing a PNP tran- 33 
sistor should yield reversed g 
indicators. f£ 



S3 



GO 

a 

z 
O 
a: 
— 
o 

LLl 



Q 
< 



Test and calibration 

To Lest and calibrate the volt- 
meter, you will need to construct 
a test jig using an actual micro- 
wave oven's power transformer. 
You will not have to remove the 
transformer, but just remember 
that during these tests that you 
will be exposing yourself to po- 
tentially lethal voltages. Use rub- 
ber gloves and have someone else 
nearby to supervise. Construct a 
string of five I-megohm, 'A-watt. 
2% resistors from the trans- 
former's high-voltage output to 
ground, with a 1N4007 diode and 
0.01-jxF/lkV ceramic capacitor 
connected as shown in Fig. 9. 
Disconnect the lead from the 
high-voltage output of the trans- 
former to the high-voltage capac- 
itor to keep the ovens magnetron 
from firing. 

Connect a DMM (set to its high- 
est DC voltage range) in parallel 
with the Microanalyzer's test 
leads, with red to the DC test 
point of the test jig, and black to 
ground. Be sure that both meters 
are set to DC and, after checking 
and covering all exposed connec- 
tions, plug in and turn on the 
microwave oven. Using your 
DMM as a reference, adjust R35 
for the same reading. Turn off 
and unplug the oven, and switch 
to the AC test point. Set both 
meters to AC, then turn on the 
oven again. If the digital display 
seems to be unstable or hunts up 
and down, adjust C13 with an 
insulated alignment tool until 
the readings settle down. After 
that has been done, adjust R34 
for the same reading as your 
DMM, Turn off and unplug the 
oven, then move the red banana 
plug to the high-voltage test jack 
J2, Turn on the oven again and 
verify that the decimal point il- 
luminates when voltage is pres- 
ent, and the reading of the 
display is shifted one digit to the 
left so that the display reads kilo- 
volts to the nearest 120 volts. If 
the accuracy is poor, you can re- 
place Rll (10 megohms) on the 
display board with different val- 
ues from zero to 10 megohms. 
This completes all testing and 
calibration. 

Use 

Since we have learned that mi- 
crowave ovens are simple devices 
with a high-voltage power supply, 
magnetron tube, and some type 




FIG. 8— THE INSIDE OF THE COMPLETED UNIT. The transformer and PC-board assembly 
are mounted in the bottom shell. 



i 



TO H.V. WINDING OF 
~6 MICROWAVE POWER 
TRANSFORMER 



ALL RESISTORS ARE 
1 MEG, 5%, Vi WATT 



CALIBRATION 
POINTS 



OAC 



DCO 



1H4007 



j_0.01nF 
"^ 1kVDC 



FIG. 9— CONSTRUCT A STRING of five 1- 
megohm, Kt-watt, 2% resistors from the 
transformer's high-voltage output to 
ground, with a 1N4007 diode and 
0.1-(jLF,1kV ceramic capacitor connected 
as shown. 

of control circuit, troubleshoot- 
ing is usually straightforward 
unless the oven has an intermit- 
tent problem. If an oven is 
"dead," check and replace, if nec- 
essary, the fuse with the correct 
type; most ovens use a ceramic 
self-quenching type fuse. Put a 
cup of water in the oven and fire it 
up. If there is still no function, or 
if it lights but doesn't heat, un- 
plug the oven and discharge the 
capacitor by connecting a test 
clip to ground, touch one, then 
the other capacitor terminal to 
ground. Now using the clip, short 



across the terminals. Since this 
method discharges the capacitor 
through the transformer first, 
the discharge will be less violent. 

The first type of tests are "stat- 
ic" tests, meaning that the com- 
ponents are checked with the 
oven unpowered and unplugged. 
Turn on the Mieroanalyzer and 
switch to "capacitor test." Con- 
nect the black lead to the capaci- 
tor terminal connected to the 
high-voltage secondary, and the 
red lead to the capacitor terminal 
connected to the anode of the 
high-voltage diode. Depressing 
S5 should indicate a good capaci- 
tor, with no flashing of the in- 
dicator. If the indicator flashes, 
or the short indictor lights, dis- 
connect all wires to the capacitor 
and check it again. 

If the capacitor checks out, 
move the black test clip to 
ground, with the red lead re- 
maining connected to the anode. 
Switch to "diode test" and press 
S5. Remember that if the tesL 
leads are connected backwards. 
all three diode test lamps will 
light. When testing capacitors 
and diodes, keep S5 pushed in 
for a few seconds. All indicators 
should be steady, as flickering 
lamps may indicate an intermit- 
tent breakdown problem. 

If the diode and capacitor are 
good, check the magnetron fila- 
ment. Full both wires off of the 



54 




USE THIS FOIL PATTERN for the main PC board if you want to make your own. 



filament connectors at the base 
of the magnetron, and with the 
black test wire still at ground, 
connect the red lead to either fila- 
ment connector and push S5. 
The Microanalyzer should be in 
the "capacitor test" mode. The 
"short" lamp should be off, un- 
less the cathode Is shorted to 
ground; however, the "capacitor 
OK" iamp may flash very slowly, 
indicating that the RF bypass ca- 
pacitors inside the magnetron 
are functioning. If the "short" 
lamp remains off, connect the red 
and black leads across the fila- 
ment and push S5; because of 
the very low resistance of the fila- 
ment, the "short" indicator will 
light. 

If all tests so far have not found 
the defective component, and the 
oven still blows fuses when oper- 
ated, the most likely cause will be 
an improperly adjusted or defec- 
tive micro switch. With the oven 
unplugged, you can use the Mi- 
croanalyzer as a continuity tester 
by connecting to each micro- 
switch and operating the door 
mechanism slowly, observing 
that the indicators show open 
and short as each as each switch 
goes through its motions. A 
sticky switch in the wrong posi- 
tion may cause a short when an- 
other switch is cycled by opening 
the oven door. You should also 
check continuity of thermal 
switches mounted to the magne- 
tron or oven cavity, if the oven 



remains dead. 

If you suspect the power trans- 
former, its three windings can 
also be checked with the Micro- 
analyzer in the "capacitor test" 
mode. The primary and filament 
windings should cause the 
"short" indicator to light, but the 
high -voltage winding will cause 
the "diode open" and "short" 
lamps to illuminate together, be- 
cause of the high reverse-EMF 
generated by the high windings 
count. 

Assuming that you have check- 
ed all components mentioned so 
far and still have not found any 
defective components using the 
static test method, active tests 
must now be performed. If the 
oven seems to be working, such 
as the lamp lights and the fan 
blows, but there is no heat, addi- 
tional tests must be done to 
check whether power is getting 
to the magnetron. 

Plug in and turn on the oven; 
listen for the three-second delay, 
then the one-second buzz that all 
magnetrons emit when they fire 
up. If you do not hear the magne- 
tron fire, unplug the oven and 
discharge the capacitor, then 
connect the red and black test 
leads across the primary of the 
transformer. Switch the Micro- 
analyzer to "volts AC," and power 
the oven. If there is no voltage 
reading, there may be a problem 
with the triac, relay or whatever 
power-switching system is used. 



If 120 volts AC is present, the fila- 
ment voltage should be mea- 
sured next. 

Disconnect the high-voltage 
wire from the filament con- 
nectors of the magnetron, so that 
only the filament wires are con- 
nected and. with the unit in the 
"AC" mode, connect the leads 
across the filament connectors 
and check for 3.1 volts AC when 
the oven is operated. If there is 
any corrosion on the terminal 
connectors, the low- voltage fila- 
ment current will have trouble 
lighting the tube. Clean all con- 
nections with contact cleaner 
and make sure all connectors are 
tight. If the problem has not been 
found yet, we must measure the 
AC and DC high -voltages. 

WARNING: this part of the dy- 
namic test involves measuring 
potentially lethal voltages so ex- 
treme care must be exercised. 
Never exceed 500 volts AC or DC 
when measuring voltage at input 
jack J 1. With the oven unplugged 
and capacitor discharged, con- 
nect the black test lead to 
ground, move the red test lead to 
the HV jack J2, and connect the 
red test-lead clip to the high-volt- 
age winding of the power trans- 
former connected to the high- 
voltage capacitor. Double check 
all connections, stand back, and 
fire up the oven. The AC voltage 
should be in the area of 1500 to 
2500 VAC. If that checks out, 
turn off and unplug the oven and 



to 

m 
-q 

-i 

m 

m 



55 




t— — ') o IB a a 

IMIEfflluU 



■ 6 INCHES ■ 



THE DISPLAY BOARD can be made using this foil pattern. 



discharge the capacitor, move 
the red test clip to the other side 
of the capacitor, and switch the 
Microanalyzer to "DC." 

Again, double check connec- 
tions and fire up the oven. A nor- 
mally operating oven will have a 
DC reading initially as high as 
4.5 kV: as the magnetron fires up 
and current is drawn from the 
power supply, the reading will de- 
crease to 2—2,5 kV and hold 
steady. Poor connections to the 
magnetron will usually show no 
voltage change, or a changing 
voltage as the connections make 
and break. A defective magne- 
tron will either not fire and the 
high-voltage reading will remain 
high, or an intermittently short- 
ing tube will cause the readings 
to be much lower than expected. 
Most better- quality ovens use a 
triac to power the transformer 
because they are much more re- 
liable than a relay, but most tech- 
nicians do not have a quick and 
positive way to test them. The Mi- 
croanalyzer can be used to check 
the triac. The triac used in a typ- 
ical microwave oven is usually ei- 
ther a one-inch square or round 
package about a half-inch thick 
with three terminals. The small- 
est terminal is the gate, or control 
pin, with the second main termi- 
nal (MT2) usually in the center, 
and the common, or first main 
terminal (MT1) opposite the gate. 

Pull off the wires from the triac 
and connect the red test clip from 
J4 (the semiconductor test leads} 
to MT2, yellow to the gate, and 
black to MT1. Indicators LED1 
and LED2 should be unlit; a 
shorted triac will light both 
LED's. Assuming the indicators 
are unlit, press test-switch S4: if 



the triac is switching, both in- 
dicators will light. If neither one 
lights, the triac is open and must 
be replaced. If only one LED 
lights, either the triac is partially 
defective, or it is an SCR. 

If the oven uses a relay, open it 
and check for pitted or heat- 
damaged contacts; if required, 
burnish them, or replace the re- 
lay. If you believe the problem to 
be a relay drive transistor, the 
transistor may be tested by con- 
necting the red J4 clip to the col- 
lector, yellow to base, and black to 
emitter. Initially, LED1 or LED2 
may be lit dimly or may be dark, 
but pressing S4 will confirm the 
type and proper operation of the 
semiconductor. For the highest 
accuracy, the semiconductor 
may have to be removed from cir- 
cuit if the readings in circuit are 
confusing. Triacs and SCR's 
should never light either indica- 
tor until S4 is depressed; a triac 
will light both LED's because it's 
an AC switching device, while an 
SCR or transistor will light only 
one indicator when S4 is pushed. 
NPN or PNP transistors may ini- 
tially light either LED1 or LED2, 
but never both; if LED2 (N-CH) is 
lit before S4 is pressed, and dims 
after it is pressed, while LED1 il- 
luminates, you have just checked 
a good NPN transistor. You must 
reverse readings for PNP 

MOSFET's, usually intimidat- 
ing to test, are easily checked 
with the Microanalyzer. Initially, 
a P- or N-channel device will il- 
luminate either LED 1 or LED2 re- 
spectively, and pushing S4 will 
cause the opposite LED to light, 
but without causing the original 
lamp to dim like ordinary bipolar 
transistors. Ordinary diodes can 



also be checked; with red at the 
anode and black at the cathode, 
LED1 will light. 

If all components check out so 
far, but your microwave oven has 
the symptom of low heating, but 
otherwise seems to be working 
normally, check the waveguide 
cover at the top of the oven cavity 
at the exit of the waveguide. If it 
is coated with grease or food resi- 
dues, it can absorb a large 
amount of power. Clean it with 
ammonia and water or, if it's bur- 
nt, replace it with the same type 
of plastic or mica material. A mal- 
functioning stirrer can also 
cause problems; that can be 
checked without even removing 
the oven cover. Stick several NE-2 
neon bulbs in a styrofoam cup 
filled with water, and turn on the 
oven. A properly operating oven 
will ionize the neon gas and the 
neon bulbs will flash on and off as 
the stirrer rotates. If some lamps 
remain on while others stay off, 
the magnetron is good; the stir- 
rer is inoperative. Check for a 
broken belt or a seized bearing in 
the stirrer mechanism. 

A quick and dirty method of 
measuring microwave power is 
to run the oven for one minute at 
full power with eight ounces of 
water in a styrofoam cup (re- 
member to start with cold water); 
a 500-watt oven will make the 
water almost too hot to stick a 
finger in, while a 750-watt unit 
will cause the water to steam. 

The final check should be a test 
of the door seal with a properly 
calibrated microwave leakage 
tester. Although the FCC allows 
five milliwatts per square cen- 
timeter, most ovens will have al- 
most unmeasurable leakage. R-E 



56 




WILLIAM P. RICE 

LAST TIME WE PRESENTED GENERAL 

concepts of electric fields and 
how they are related to static elec- 
tric charges. We saw that the E 
field in empty space accounts for 
the forces between such charges. 
In this article, we'll see how the 
familiar units of volts and am- 
peres are related to each other. 
Ohm's law and the concept of an 
E field in materials will be dis- 
cussed with the help of a simple 
quantum theory viewpoint. 

Potential 

To quasi-statically move a 
charge q from point a to point b 
in an E field, a force that is infi- 
nitely close to being equal and op- 
posite to the Coulomb force must 
be applied to q. That force is 
— qE= — F c i as shown in Fig. 1. 
As we discussed in our previous 
article, when moving around a 
closed path 

fEdl = 0, 
or 

VxE = 
at all points. So in moving the 
charge around a closed path 
-/oE-dl = 0. 

The dot product gives the magni- 
tude of force times distance in 



the direction moved, which is the 
work done or change in the po- 
tential energy AU. The energy ex- 
pended in moving along the path 
from a to b is just the sum of the 
contributions along that path, as 
defined in the calculus notation 

r b 
AU ab =- qE-d I (newtonx meters = joules). 

Ja 

The energy change is indepen- 
dent of the path taken from point 
a to b, and the E field follows the 
laws of conservation; whatever 
energy is expended in moving the 
charge from point a to b is re- 
covered when the charge moves 
from b to a. The energy is said to 
be stored in the E field since the 
field is responsible for the force. 

Dividing by the charge gives us 
the change in energy per unit 
charge, the potential or voltage at 
point b with respect to a is 



-I E- d I (joules/ coulomb = volts). 

The use of the name potential is 
perhaps unfortunate because it's 
easy to confuse the term with po- 
tential energy. 

Recall also that since V x E = 0, 
E must be the gradient of a scaler 



field, which we now see is the po- 
tential V, therefore 
E= -VV (volts/meter = newtons/cou lorn b). 
Along a surface of equal poten- 
tial, there would be no change in 
V per length dl. Perpendicular to 
that surface the change in V per 
length would be a maximum, 
which is what the gradient tells 
us. 

Since the field is obtainable by 
linear superposition, the poten- 
tial difference is simply the sum 
of the potentials. For example, 
V ac =V ab + V b ,. That analysis is 
the basis of Kirchoffs voltage law, 
which states that the algebraic 
sum of the voltage rises and 
drops around a closed path must 
equal zero. 

Electric current 

Imagine a Gaussian surface in 
space through which a number 
of q charges are moving, as 
shown in Fig. 2. (We are not con- 
cerned with the type of field influ- 
encing the motion, only that & 
there is motion.) The current ^ 
across that surface is defined as m 
the charge per unit time (in sec- w 
onds) crossing the surface. In m 
order to calculate that, divide the ^ 
surface into an infinite number 52 



57 



of infinitesimal surfaces, ds. The 
charges move with velocity v 
through each surface. If there are 
n charges per unit volume, then 
the current density, or charge per 
unit area is 

J = nqv = pv (CVm 2 s). 
Multiplying that by the effective 
area and summing the contribu- 
tions by integration gives the 
total current 

I = /J-ds {C/s = amperes). 

Positive charges flowing in one 
direction can be considered 
equivalent to negative charges 
flowing in the opposite direction 
(the Hall effect is a common ex- 
ception) since both J and ds 
would then be negative. That is 
why a circuit can be analyzed in 
terms of either conventional cur- 
rents or electron currents. 

The way current is defined is 
similar to the way we explained 
electric flux w except that flux is 
an apparent flow while current is 
due to an actual flow of charge. 
Charge conservation tells us that 
whatever charge flows into the 
surface must also flow out unless 
the current density inside is 
changing in time. That is the 
basis of Kirchhoffs current law, 
which tells us that the sum of the 
currents flowing into a junction 
is equal to the sum of the cur- 
rents flowing out of that junc- 
tion. Shrinking the Gaussian 
surface down to a single point 
and taking the ratio of the rate of 
change in current to the rate of 
change in volume gives the diver- 
gence 



v- j = 



4?(C/m 3 s). 



03 

O 



o 



o 

LU 



2 

Q 
< 

58 



The partial differential symbol 
d, as in d, means an infinitesimal 
change in something. It also re- 
minds us that we're only inter- 
ested in p's change with respect 
to time, t. The negative sign indi- 
cates that a decrease in p, a nega- 
tive r)p/dt, gives a positive 
divergence. The net charge must 
therefore flow out through the 
surface. 

Conductivity 

Up until this point we have 
been concerned only with 
charges in empty space. The 
space of solid materials, however, 
is far from empty. Atoms are lo- 
cated at positions called lattice 
points. An external E field ap- 
plied to a solid material causes 
the electrons with a - e charge to 




FIG. 1— AN ELECTRIC CHARGE q is 
moved quasi-statically from point a to b in 
a static E field along either path, com- 
posed of an infinite number of lengths dl, 
by an external force qE (not shown). The 
work done or change in energy is the 
negative of the sum of all the qE-dl's along 
the path. 




FIG. 2— CURRENT DENSITY J is the 
number of charges q per unit volume mov- 
ing with velocity v through an infi- 
nitesimal section ds of the Gaussian 
surface. The total current is found by sum- 
ming J-ds over the entire surface. Any 
charge that comes in through one ds must 
leave through another. Any net outflow 
must be at the expense of the charge den- 
sity enclosed by the surface. 



ITRMI ENERGY 




MOMENTUM 

FIG. 3— ENERGY VERSUS MOMENTUM 
for electrons in a material. Temperature 
and lattice effects are neglected. Each 
electron, represented by a dot on the 
curve, has a unique energy state. Those 
are the lowest states available. The high- 
est occupied energy is called the Fermi 
energy. 

move. Quantum theory must be 
used to describe the effects of 
temperature and the lattice upon 



the motion of charges. 

The electrons are in a state de- 
scribed by their energy, mo- 
mentum, and spin. No two 
electrons can be in the same 
state. Electrons can change ener- 
gy only by moving to a neighbor- 
ing unoccupied energy state. 
Figure 3 shows the energy versus 
momentum states, neglecting 
the effects of temperature and 
the lattice. The two possible spin 
states for each electron are not 
shown for clarity. 

The more electrons there are in 
the material, the higher the high- 
est occupied energy state, or Fer- 
mi level. Only electrons near the 
Fermi level can respond to exter- 
nal effects such as thermal ener- 
gy and electric fields. Supplying 
thermal energy excites some elec- 
trons to energies just above the 
Fermi level, leaving unoccupied 
states just below. The Fermi level 
is then taken as the energy with 
50% occupancy. Electrons that 
can change energy, and hence 
momentum, are called con- 
duction electrons. Thermally ex- 
cited electrons have random 
momentum and velocity, and do 
not produce a net current. 

Electrons act as waves and, 
therefore, experience inter- 
ference effects due to interaction 
with the lattice. At certain wave- 
lengths, standing waves result 
which produce energy gaps, as 
shown in Fig. 4. If only some of 
the energy states up to the gap 
are occupied or the gap is very 
small, the material will have 
many conduction electrons since 
little external energy is required 
to excite an electron to a higher 
state. Such materials are good 
electrical conductors. A good in- 
sulator (or dielectric) has oc- 
cupied states up to a relatively 
large gap. A large amount of ex- 
ternal energy is required to excite 
electrons to higher energies in a 
dielectric material. A material 
with a large gap and many oc- 
cupied lower states exhibits no- 
ticeable electrical resistance. 

If a potential difference is 
maintained across a material, an 
electric field is established. Con- 
duction electrons will be sub- 
jected to a force F, which is equal 
to — eE. Electrons tend to acceler- 
ate, and then "collide" and lose 
energy to the lattice. If t is the 
average time between collisions, 
which is temperature dependent 
due to thermal motion of the lat- 



CONDUCTOR 
ENERGY 



INSULATOR 
ENERGY 



A 


i 




,y 


r 


GAP 


i 




, '\ 


y , 




1 


) 









i 
i 


1 

GAP 


V 


/ , 



MOMENTUM 

a 



MOMENTUM 
b 



FIG. 4— ENERGY VERSUS MOMENTUM lor electrons is a lattice of atoms. The gaps in the 
curves result from interference effects with the electron waves. In a conductor (a) the 
levels below the gap are partially occupied. External energy excites electrons to the 
unoccupied energy states. That allows them to participate in an electric current. In an 
insulator (b) the levels below the gap are filled and the energy gaps are large. Electrons 
cannot participate in a current unless a large amount of external energy is supplied. 



tice atoms, then the average elec- 
tron momentum is 

Ft= -eET = m + v (N-s = kg-m/s) 
where m is the electron mass, 
and v is the average velocity. Solv- 
ing for the velocity and substitut- 
ing into the equation for current 
density gives us 

m 

which is the vector form of Ohm's 
law. Since the number of elec- 
trons n and t are properties of the 
material, the conductivity 
n = ne^/m (C 2 s/kg = 1/{ftm) 
is a property of the material. The 
resistivity is defined as r = l/cr. If 
the material is of uniform cross- 
sectional area S and of length L, J 
is uniform and normal to ds, 
therefore the current is 

l« JS = 0j- S 

or V = IR where R = rL/S is resis- 
tance in more familiar units of 
ohms. 




In metals, increasing the ther- 
mal energy excites electrons 
mainly into the unoccupied 
states of the lower band, but the 
time between lattice collisions 
decreases. Increasing the tem- 
perature increases the resis- 
tance. In some other materials 
resistance decreases with in- 
creasing temperature because 
the number of conduction elec- 
trons exceeds the effect of in- 
creased collision time. 

Due to the low velocity of elec- 
trons in most solids, the magnet- 
ic effects can be neglected. 
Conduction becomes more com- 
plicated in gases and liquids 
since the atoms can also move, 
and velocities can become greater 
than in solids. 

The electric field in materials 

When a material is placed in an 
external electric field E , the wave 
functions of the atoms are 
changed. The net effect is that 



INSULATOR 



©-© 






H 



— E| 



-*. E. 






FIG. 5— MATERIALS IN AN EXTERNAL ELECTRIC FIELD E exhibit electric polarization. 
The resulting separation of positive and negative charge regions produce electric dipole 
moments qR. where q is taken as positive. In a conductor (a), enough electrons are free to 
move to create a depolarization field E d equal and opposite to E . The internal electric 
field E, E„ E d is zero. In an insulator or dielectric (b), electrons are restricted in 
movement and E, is non zero. In both cases, the polarization or dipole moment per unit 
volume P is related to E d . The vectors are shown outside the material for clarity. 



the regions with probability of 
finding electrons are shifted in 
the -E direction while the re- 
gions with probability of finding 
the positively charged nuclei are 
shifted in the direction of + E D 
(Fig. 5). The shifts may not exact- 
ly align parallel to E . and may 
not all be uniform except in what 
we call simple materials. A nega- 
tive surface charge develops on 
the material near the source of 
E„, and a positive surface charge 
develops on the opposite side. We 
say the material has an induced 
charge, or that it is electrically 
polarized. 

The induced charges produce a 
field E d in the opposite direction 
to E in the material. In a very 
good conductor, there are 
enough free charges so that E d 
equals E Q , and the average field 
inside is zero. That is why metal 
is an effective shielding material, 
at least for static fields. Outside 
the conductor the E field vectors 
are changed so that they are nor- 
mal to the surface. 

In dielectrics, the large energy 
gap means the electrons are elas- 
tically attached to the lattice and 
only slight shifts are experi- 
enced. E and E d don't cancel 
each other completely. In a simple 
dielectric, pairs of internal 
charges, — q and +q, are sepa- 
rated by a distance R taken in the 
direction of E , from -q to 4-q. 
Those pairs of negative - q and 
positive +q charges are called 
electric dipoles. The vector quan- 
tity, qR, is called the electric di- 
pole moment. If there are n 
dipoles per unit volume, then a 
measure of the polarization can 
be expressed as 

P=n(qR)£ (Cm/m 3 = C/m z ), 
which is called the dipole mo- 
ment per unit volume, t, is a 
function of the alignment and 
ranges from to 1. For simple 
materials £=1. Since n, q, R, and 
£ depend on the material, 

P = e xE 

where x, the electric suscep- 
tibility, is a measure of the ease of 
polarization of the material. E is 
present to maintain correct 
units. The so called depolariza- 
tion field E d is equal to -7P/e , 
where 7 is a number between -** 
and 1 , and is related to the geom- 3 
etry of the material. E d is not, in 1 
general, very useful. ro 

The surface charge rr b is an ac- id 
tual accumulation of charges ^ 
con tin ued on page 82 ^ 

59 



m 

y 

z 

Q 

EC 

F 

o 



Q 



If your home or office has more 
than one telephone extension, 
you've probably had the unpleas- 
ant experience of picking up the 
phone only to find it already in 
use. You may get an angry re- 
sponse from the person on the 
other end. If a modem is in use, 
you'll be greeted by the obnoxious 
squall of two computers ex- 
changing bits. Such an interrup- 
tion usually means a lost 
connection, or the corruption of 
a file being transferred. 

A solution to that problem is 
the Phone Sentry — an inexpen- 
sive, simple, reliable indicator 
that warns you when a phone ex- 
tension is in use. The Phone Sen- 
try is easy to build and install in 
one evening, and presents no 
load to the phone line. It's small, 
inconspicuous, and costs only $5 
a copy. 

How it works 

To understand how the Phone 
Sentry works, you need to under- 
stand how the telephone system 
works — or, at least, how the local 
subscriber loop works, since 
that's the part that enters into 
your house. 

The telephone line is held at 
about 45 volts DC by the local 
switching office when it's hung 
up. When a telephone is taken off 
its hook, a IK load brings the line 
down to 6 volts DC. The line stays 
at 6 volts DC until you hang up, 
then it returns to 45 volts DC and 
is disconnected. 

The Phone Sentry operates by 
monitoring the telephone line 
voltage and switching on a flash- 
ing LED whenever the voltage 
drops below 20 volts. The Phone 
Sentry can be placed anywhere 
on a phone line, not Just on an 
extension in use. 

Circuit operation 

The Phone Sentry circuit is de- 
ceptively simple, yet elegant in 
design. At the heart of the circuit 
is IC1, a CMOS CD4093B quad 
nand gate Schmitt trigger. 

Ordinary CMOS gates switch 
midway between the voltage of 
the positive and negative sup- 
plies. For a circuit powered from 
5 volts, this point (called 0,5 V + } 
is 2.5 volts. When the input volt- 
age rises past or falls below that 
point, the output will switch. 
Normally, that's a desirable 
characteristic, and is one of 



HE PHOIXI 

EIMTR 

"Stop! Don't pick up that 

phone!" The Phone Sentry 

will warn you when a 

telephone extension 



is in use. 

DANIEL B. COOPER 



fltrt*,fff"t*tr*tf" 



CMOS's good points. However, 
when a CMOS input is presented 
with a slowly changing or noisy 
input, the symmetrical switch- 
ing characteristic can cause the 
circuit to jitter or oscillate as the 
input nears the 0.5 + V point. 

The Schmitt trigger input han- 
dles noisy environments by sepa- 
rating the rising and falling 
voltage-switching points. A 
Schmitt trigger input will react 
to a rising input voltage only 
when it passes a threshold that is 
higher than 50% of the supply 
voltage, usually about 70%, or 
0.7 +V. A falling input voltage 
will cause a change only when it 
falls below a much lower thresh- 
old of about 30% of die supply, or 
0.3 + V. An input voltage between 
those two thresholds will have no 
effect until it rises above 0.7 + V, 
or falls below 0.3 +V. 

The region between the 70% 
and 30% switching levels is 



called the hysteresis gap, or dead 
band. Hysteresis permits a 
Schmitt trigger input to respond 
very cleanly to noisy or irregular 
input signals. It also permits 
some fancy tricks, such as one- 
gate oscillators. It is the latter ca- 
pability for which a Schmitt nand 
gate is used in the Phone Sentry. 

Figure 1 shows a block diagram 
of the Phone Sentry. The four 
gates of the CD4093B are used as 
three separate elements. One 
Schmitt-trigger nand gate acts as 
an input comparator to monitor 
a phone line. It in turn gates an- 
other nand gate used as an os- 
cillator, which drives a high- 
current buffer for LED1. 

The schematic of the Phone 
Sentry is shown in Fig. 2, with its 
circuit waveforms at critical loca- 
tions shown in Fig, 3. Bridge rec- 
tifier Dl — D4 eliminates any 
phone-line polarity problems. It 
also removes the 80-volt peak-to- 



60 



peak ring signal, which could 
damage the Phone sentry or 
make LED1 flicker. 

The output of the bridge rec- 
tifier is divided down by R1-R2, 
with 27% of the input voltage 
reaching ICl-a. 27% represents 
the voltage divider of the 
[R2/(R1 +R2)] ratio, which equals 
(1 megohm/[1 megohm + 2,7 
megohm)] = 0,27 

The bridge always presents two 
of the four diodes as a phone-line 
load, D1-D4 or D2-D3, dropping 
the line voltage down by 0.7 volts 
DC each, or 1.4 volts total. Since 
the input impedances of pins 12 
and 13 of ICl-a are almost infi- 
nite, they draw no current. What 
appears across Rl and R2 in se- 
ries should be about 

45 V- 1.4 V = 43,6 V. 
The voltage at pins 12 and 13 
with the phone hung up is there- 
fore 

43.6 Vx 0.27 = 11. 78 V, 
which is 2.78 volts above the 9- 
volt DC supply. The IC, however, 
is protected from overcurrent 
burnout by Rl and internal di- 
odes. When an extension is in 
use, the 6 volts on the line goes 
down to 

(6 V- 1.4 V) x 0.27 = 1.24 V. 

Capacitor CI filters out small 
spikes that can be generated dur- 
ing the ringing cycle, protecting 
the IC and eliminating any re- 
sidual tendency of the LED to 
flicker. 

Because the comparator is a 
Schmitt nand gate, its output 
(pin 11) will be low whenever the 
input voltage is above about 6.3 
volts (70% of 9 volts), and high 
whenever the input drops below 
about 2.7 volts (30% of 9 volts). 
Those switching values fit per- 
fectly with the 11,78 and 1.24 
volts generated from the phone 
line by the rectifier and divider. 
The output will be low when all 
phones are on-hook, and high 
when any phone is picked up. or 
a modem is connected to the line. 

The LED could be driven di- 
rectly by ICl-a, but Bl would be 
drained in about 10 hours be- 
cause LED1 draws 10 milliamps 
when lit. To extend battery life to 
at least 100 hours. ICl-b, the low 
5% duty-cycle oscillator, is gated 
bylCl-a, driving LED land giving 
a bright flash with much lower 
current drain. 

The output of the comparator 
is used to gate an oscillator on 
and off. That oscillator consists 




BRIDGE SCHMITT-TRIGGER TIMING 



RECTIFIER 



COMPARATOR 



GATED DRIVER INDICATOR 
OSCILLATOR 



FIG. 1— BLOCK DIAGRAM OF THE PHONE SENTRY. The rectified phone-line voltage 
drives a comparator, whose output gates a low duty-cycle oscillator. The oscillator drives 
a CMOS buffer/driver. The period and duty cycle of the oscillator are controlled by timing 
components R3, R4. and C2. 



R1 

2.7MEG 






FIG. 2— SCHEMATIC OF THE PHONE SENTRY, using a CD4093B quad NAND-gate Schmitt 
trigger. The green (tip) and red (ring) phone-line wires are polarity-independent due to 
D1-D4. Input comparator IC1-a gates ICt-b, a single-gate oscillator, which drives ICI-c and 
-d, used in tandem as a high -cur rent buffer/driver. 



PARTS LIST 

All resistors are Vi-watt, 5%. 

R1 — 2.7 megohms 

R2— 1 megohm 

R3— 4.7 megohms 

R4— 220,000 ohms 

Capacitors 

C1—-0.005 p.F. 100 volts, disc or 
monolithic 

C2— 0.33 (jlF, 16 volts, tantalum or 
electrolytic 

Semiconductors 

D1-D4— 1N4001 diode 

D5—1N4148 diode 

1C1— CD4093B quad Schmitt trigger 
NANo-gate 

LED1 — light-emitting diode, any size or 
color 

Miscellaneous: 9-volt alkaline battery 
with clip, PC board (see foil pattern), 22- 
AWG wire, plastic case (optional), LED 
mounting clip (optional), modular plug- 
to-bare wire phone cable (optional), 
two-way phone jack duplexer, 14-pin 
D!P IC socket. 



both inputs are now high, the 
output switches low. The charge 
of C2 is drained, partly through 
R3, but more quickly through R4 
and D5. When the voltage at pin 1 
drops below the Schmitt input's <£ 
lower threshold, the output of ^ 
the gate switches high, and the cjj 
capacitor begins charging again ro 
through R3. When the capacitor 3 
voltage reaches the Schmitt's up- 5 
per threshold, the output switch- 2 



THE PC-BOARD FOIL PATTERN FOR the 
Phone Sentry. 

of a second Schmitt nand gate 
(ICl-b). R3, R4, C2, and D5. 
When pin 2 of IC1 is held low by 
the comparator, the output of the 
gate is held high. That output is 
used to charge timing capacitor. 
C2, through timing resistor R3. 
The junction of components R3 
and C2 is connected to pin 1. 
With the output held high, the 
charge on C2 will rise to the level 
of the supply voltage. 

When a phone is picked up and 
the loop voltage drops, the com- 
parators output goes high and 
the oscillator is enabled. Since 



61 



m 
o 
z 
O 

E 

ts 

LU 
_l 
UJ 

Q 

Q 
< 
EC 



43.6 



PHONE LINE, VDC 

(ON-HOOK) 



4.6 



(OFF-KOOK) 



, , IC1-a PINS 12 AND 13, VDC (RELATIVE TO CIRCUIT GND) 



11.78 
9-t 



2.7 
t.244- — * 



PROTECTED 
BY HI AND 

INTERNAL if-i-api : 
DIODES IN 1 ' 
IC1-a g 



VDC 




FIG. 1— CIRCUIT WAVEFORMS OF THE Phone Sentry. Shown are the voltages on the 
phone line, pins 12 and 13 of IC1-a, pin 11 of IC1-a, pin 3 of IC1-b, pin 1 of ICI-b (the voltage 
across C2), and across LED1. 



I r-i 




L^, 



- R3— ™ 
4«w -C2- + _ R4 _^_ 



PHONE 

LINE 



■Jrf# 



FIG. 4— THE PARTS PLACEMENT DI- 
AGRAM of the Phone Sentry. You can 
mount LED1 In several ways, depending 
on how you mount the PC board. 



es low again and the process 
repeats until the gating input is 
again brought low by the phone 



going back on-hook. 

The output of the oscillator 
(pin 3) is inverted and used to 
drive the indicator LED. When 
the oscillator's output is high, 
the output of the driver (pins 10 
and 4) is low, and the LED is off. 
When the oscillator output is low, 
the driver output is high, and the 
LED is on. Since the capacitor 
discharge time (oscillator output 
low) is much shorter than the 
charge time (oscillator output 
high), the LED is on much less 
time than it is off, resulting in a 
very low duty cycle, and low bat- 
tery drain. 

Because the capacitor starts 
each cycle charged much higher 
than the Schmitt input's upper 
threshold, it takes longer to dis- 



charge to the lower threshold the 
first time. Therefore, the first 
flash of the LED is longer and 
brighter than those that follow. 
That's a nice touch, because all of 
the Phone Sentries in the house 
will give an initial bright flash 
when a phone is first picked up to 
answer a call. 

Construction and installation 

The Phone Sentry can be as- 
sembled on either a PC board, 
shown here, or on perforated 
construction board of similar 
size. The PC board is about the 
size of Bl, so housing the unit is 
simple, and its construction is 
straightforward. Figure 4 shows 
the parts placement diagram; 
use a socket for 1C1, and install it 
using proper anti-static han- 
dling techniques. 

The Phone Sentry is small, 
with several installation options. 
Once you decide how to mount it, 
you can select how to wire both 
the phone line and LED1. If you 
put the Phone Sentry inside an 
extension or a wall-mount jack, 
then solder a foot of 22-AWG wire 
to each input terminal. 

If you use a small case for plug- 
ging into a wall socket, solder the 
green (tip) and red (ring) wires of 
a modular plug-to-bare-wire 
phone cord, and clip the yellow 
and black wires. You may want to 
solder LED1 directly to the PC 
board, or mount it in a visible 
location with two 6-inch pieces of 
stiff wire. 

You can mount both the PC 
board and Bl in a standard desk 
phone. Open the phone and se- 
cure both the PC board and bat- 
tery clip to the baseplate with 
double-sided foam tape. Drill a 
small hole in the dialing button 
escutcheon, and use silicone sea- 
lant or an LED clip to mount 
LED1. Connect the two input 
wires to the tip and ring wires, 
insert Bl, replace the cover, and 
plug the phone back in. 

If there's no space for the Phone 
Sentry and Bl, use a small plastic 
box on the side of the phone for 
the PC board, Bl, and LED1, and 
pass the tip and ring wires 
through a hole in the box and 
phone case to the connecting 
points inside the phone. For a 
wall phone, mount the same case 
near the wall jack and run the 
wiring into the wall jack, so it's 
independent of the phone. R-E 



62 



ITS BEEN LESS THAN A DECADE 

sense the compact disc was in- 
troduced. In that short time, the 
CD has brought high-quality au- 
dio reproduction to the masses. 
and taught us to appreciate good 
sound. We're not exaggerating 
when we say that the CD has 
changed the way we listen to mu- 
sic. 

It's rare for a new technology 
and format to catch on so quick- 
ly — especially one that threatens 
to make its predecessors ob- 
solete. CD was a success not only 
because of consumer acceptance , 
but because it also offered some- 
thing to manufacturers, record- 
ing companies, and retailers. 

It wasn't the CD's "gee whiz" 
appeal — nor was it the promise of 
perfect audio reproduction — that 
caused sales to catch fire. It was 
convenience. When compared to 
the LP that it replaced, CD's were 
a dramatic breakthrough. They 
can store more audio in a pack- 
age a fraction of the size. They 
can be lent to even your most 
careless friends without getting 
scratched. They even play back 
more conveniently, because you 
can skip tracks that you don't 
want to listen to, or re-arrange 
the order in which the songs play 
back. 

It's convenience, also, that 
makes the venerable compact 
cassette our music medium of 
choice. {Cassettes outsell CD's by 
a ratio of about 1.5:1.) They fit in 
your shirt pocket, and they stand 
up reasonably well to abuse. 
They're ideal for use in a car or in 
a personal stereo because they're 
relatively immune to shocks. So 
what if they can't come close to 
the audio quality of a CD or even 
an LP? 

How about DAT? 

In the belief that consumers 
had fallen so much in love with 
the idea of digital audio because 
of their exposure to CD, Japa- 
nese manufacturers reasoned 
that Digital Audio Tape (DAT) 
would be to the CD what the com- 
pact cassette was to the LP. Unfor- 
tunately, it didn't work out that 
way for a number of reasons. 
First, the record industry, 
spearheaded by the RIAA (Re- 
cording Industry Association of 
America), threatened lawsuits 
against any Japanese manufac- 
turer who exported the DAT ma- 




Two new digital audio formats — Sony's 

Mini Disc and Philips' Digital Compact 

Cassette— promise to battle each other as 

they create consumer confusion. 



chines to the U.S. The RIAA was 
concerned about DAT's potential 
to make virtually perfect copies of 
CD's. (They seemingly missed the 
fact that, for most people, cas- 
settes do the same thing. And de- 
spite that, pre-recorded cassettes 
have outsold both LP's and CD's 
combined since 1982! They've 
outsold blank tapes as well.) The 
threats of lawsuits were enough 
to stop DAT dead in its tracks, 
despite considerable accolades 
for the format in the audio and 



general press. 

Although some DAT machines 
were available on the "gray mar- 
ket" of unofficially imported 
goods, DAT officially arrived in 
the U.S. market last year — with 
generally disappointing results. 
Whether it was the years of delay, 
the taint of the lawsuits, the ex- 
pense of the machines, or the 
lack of pre-recorded software that 
have killed DAT in the consumer 
market, we'll never know for 
sure. Perhaps DAT failed because 



09 

m 

m 
CD 

m 
x 
— . 

to 



63 



107.5 



o 

z 

i 

O 



LU 

Q 
D 
< 



8x1 

- 


185 
95=1560 
10 

| 





1 


z 


3 


4 


5 


6 


Li 


7 


8 



1852,5 



HEAD ROTATION 




EIGHT TRACKS OF MUSIC DATA are con- 
tained on each "side" of the Digital Com- 
pact Cassette, as shown in a. (All 
dimensions shown are in micrometers.) 
The DCC head shown in b is manufac- 
tured using thin-film techniques. It con- 
tains a set of 8 digital recording and 
playback heads as well as two analog 
playback heads, 

it doesn't offer the avarage con- 
sumer anything that they're not 
already getting from their favor- 
ite compact cassettes. 

Although the compact cas- 
sette- — even with its inherent 
problems — is just fine for most 
people, Philips, the originators of 
the compact cassette, was con- 
vinced that the format could be 
improved, and that consumers 
would buy into the updated for- 
mat. Thus. DCC, the Digital 
Compact Cassette, was born. 

Enter DCC 

In January of this year. Philips 
announced that "a new era of au- 
dio reproduction has started." 
DCC, a digital extension of the 
compact cassette, would offer 
"the best opportunity available 
for consumers and industry to 



enter into the field of digital re- 
cording." Tandy Corporation an- 
nounced that they would be the 
first U.S. licensee of Philips' tech- 
nology, and would introduce a 
home recording deck in late 
1992. 

The most Important feature of 
DCC is that it doesn't make the 
familiar cassette obsolete. All 
DCC players will play back exist- 
ing analog cassettes, so even 
when you make the jump to DCC, 
you can still listen to your exist- 
ing library of tapes. (You won't, 
however, be able to record analog 
cassettes on your DCC machine, 
or play DCC tapes on your stan- 
dard cassette deck.) That "back- 
ward compatibility" could con- 
vince some consumers to up- 
grade to DCC even though they 
like what they already have. After 
all, an upgrade won't just give 
them better sound, but as well 
see, more convenience as well. 

A DCC deck is essentially a 
standard cassette recorder that 
includes some extra digital elec- 
tronics and a new head design. 
The dimensions of a DCC cas- 
sette are essentially the same as 
that of a standard cassette, but 
the digital cassette's sides are 
flat — the case doesn't get fatter 
where the head enters the shell. 
Also, since the DCC standard de- 
mands that all DCC players fea- 
ture auto-reverse, there's never a 
need to flip the tape over, so you 
don't need to have holes for the 
reels on both sides of the cas- 
sette. That means that one full 
side of the cassette can be used 
for information and graphics — 
something the recording compa- 
nies love. 

The spool holes and the tape 
surface are protected against 
dust and fingers by a sliding met- 
al cover, which also locks the tape 
hubs. There's no need for an car- 
rying case, so the digital cassette 
is easier to use and store, es- 
pecially in a car. 

The key to maintaining com- 
patibility with standard cas- 
settes is a new thin-film semicon- 
ductor head, manufactured 
using a process similar to that 
used for integrated circuits. The 
first layer of the head contains 
one set of 9 magneto-resistive 
heads for digital playback, and a 
pair of similar heads for analog 
playback. On the second head 
layer is one set of 9 integrated 




0.02 05 1 H.'z 0.5 i 2kHz 5 tfj~20 
FREQUEMCY-kHz 



100 



80 
60 

t 20 





0.02 0.05 0.1 0.2 0.5 1 2kHz 5 10 20 
FREQUENCY-kHz - 




0.020.05 0.1 0.2 0.5 1 2kHz 5 
FREQUENCY-kHz 



10 20 



PHILIPS' PASC ENCODING ignores 
sounds that are below the hearing thresh- 
old (a). Of the signals shown in b, oniy A 
would be recorded because B, below the 
hearing threshold, would not be heard. 
The hearing threshold, however, varies 
dynamically depending on what other sig- 
nals are present, in c, signal B has altered 
the threshold, making A inaudible. 

recording heads for digital re- 
cording. Well see shortly why 9 
digital heads are required. 

PASC makes it work 

The key to the DCC system is 
the a new digital coding tech- 
nique called PASC, or precision 
adaptive sub-band coding. The 
goal of PASC is to produce a sig- 
nal equivalent to that of a CD. 
The results? A dynamic range 
better than 105 dB, and a total 
harmonic distortion, including 
noise, of less than 0.0025% 

PASC is based on two impor- 
tant phychoacoustic principles. 
The first is that we can hear 
sounds only if they're above a cer- 
tain level, called the hearing 
threshold. The second is that 
loud signals mask soft ones by 
raising the hearing threshold. 



64 



The hearing threshold, as you 
might expect, varies from person 
to person. Even a very sensitive 
ear, however, won't be able to 
hear a sound if it is masked by a 
louder sound. (You couldn't, for 
example, hear an unamplified vi- 
olin at a rock 'n' roll concert! ) The 
theory behind PASC's efficiency 
can be expressed by the ques- 
tion, "If you can't hear it, why 
record it?" 

During encoding, the PASC 
processor analyzes the audio sig- 
nal by splitting it into 32 sub- 
band signals. By continuously 
taking into account the dynamic 
variations of the hearing thresh- 
old, the PASC processor encodes 
only the sounds that will be audi- 
ble to the human ear. Each sub- 
band is allocated the number of 
bits that are required to accu- 
rately encode the sound within it. 
If a subband doesn't require my 
bits — because it contains sounds 
that are masked, for example — 
its bits are re-allocated to other 
subbands so that the sounds 
within them can be encoded 
more accurately. On average, the 
PASC system needs to encode 
only one quarter the number of 
bits that a CD or DAT encoder 
would to reproduce a given audio 
signal. 

The encoded data is multiplex- 
ed into an 8-channel data 
stream, and error-detection and - 
correction codes are added. The 
eight channels are recorded on 8 
parallel tracks on the DCC tape. 
The ninth track can be used to 
carry auxiliary data, such as 
song titles, recording times, and 
the like). The auxiliary track 
could be used to generate hun- 
dreds of characters of text per 



TERBIUM FERR1TE COBALT 
MAGNETIC MATERIAL 



POLYCARBONATE RESIN 





A PROTOTYPE MINI DISC player and a pre-recorded disc. 



ALUMINUM REFLECTIVE LAYER 

PROTECTIVE LAYER 

THE MINI DISC is composed of 4 layers. 



second, so decks could include 
readouts for song lyrics or other 
information about the selection. 
DCC, an elegant extension of 
the most popular music carrier 
we have, seemed to be a sure-fire 
hit. It had something for every- 
one, including hardware man- 
ufacturers, record companies, 
retailers, and consumers. It now 
appears, however, to have run up 
against a formidable competitor: 
Sony's Mini Disc. 

Sony's Mini Disc 

In May of this year, in what 
seemed to be a deliberate attempt 
to derail DCC before it got mov- 
ing, Sony announced a brand 
new recordable audio format, the 
Mini Disc or MD. Sony, however, 
denied that their MD was meant 
to compete with DCC. In re- 
sponse to the question of what 
MD replaces, the President of 
Sony Corporation of America an- 
swered "We are replacing 
nothing. We are Creating new 
markets." 

The Mini Disc format is specifi- 
cally designed for portable ap- 
plications (personal stereos, 
boom boxes, etc.) and is slated for 
introduction, conveniently, in 
late 1992 — the same time that 
DCC decks are due. The disc, 
about 2'/2 inches in diameter, 
looks — -and acts — like a cross be- 
tween a compact disc and a micro 
floppy computer disk. Like a 
compact disc, the Mini Disc is an 
optical medium — it is read by a 
laser and can store up to 74 min- 
utes of digital audio. Like a floppy 
disk, the mini disc can be mag- 
netically recorded again and 



again. 

How did they manage to get the 
same capacity as a CD on a disc 
that has about l A the surface 
area? Interestingly, by treating 
audio in much the same way as 
DCC does. Sony's encoding 
scheme, which is called ATRAC, 
or adaptive transform acoustic 
coding. Is also based on the psy- 
choacoustic principles regarding 
the threshold of hearing and the 
masking effect. 

Because the ATRAC encoder ig- 
nores sounds that fall below the 
threshold of hearing (which var- 
ies dynamically because of signal 
masking) it can encode data five 
times more efficiently than CD or 
DAT systems. That's even better 
than DCC's 4:1 advantage! 

Can a recording that "leaves 
out 80% of the bits" sound as 
good as a CD? In theory, if all 
you're leaving out is things you 
can't hear, then yes. In practice, 
we don't know yet. At Sony's an- 
nouncement, they demonstrated 
a prototype by playing some pop/ 
rock for a half minute or so. It 
sounded OK, we guess, consider- 
ing that the listening environ- 
ment was a crowded hotel 
meeting room. No A/B com- 
parisons were provided between 
CD and MD. Sony claims that 
"only 2% of the population will be 
able to hear the difference." 

The Mini Disc is constructed of 
four layers, including a newly de- w 
veloped magnetic layer of ter- S 
bium ferrite cobalt. Since mag- m 
ne to-optical discs can't come in §5 
contact with the recording 3 
heads, it's important that the — 
magnetic material be able to 2 



65 



CTj 

u 

z 

o 



LU 

6 

Q 
< 

a: 



MAGNETIC HEAD 


WRITING SIGNAL 
1 


1 





1 


















1 


t 


) 


( 

































DISC 
ROTATION 



NEW 



OLD 



CEEEEEI tl*l#f!W 



MO LAYER 
[CROSS-SECTIONAL VIEW 



OBJECTIVE LENS 




LASERt 



MAGNETO-OPTICAL OVERWRITE TECHNOLOGY. When the magnetic layer is heated by 
the laser, it becomes possible for the magnetic head to change its polarity. The polarity is 
then detected by the laser during playback by noting the direction of reflection. 



change polarity when subject to a 
very small magnetic field. The 
new material fills the bill. 

The Mini Disc requires both a 
laser and a magnetic head for re- 
cording. When the magnetic 
layer is heated by the laser (to a 
temperature of about 400°F), it 
loses its coercive force — that is, it 
becomes very easy to magnetize. 
The head then supplies a mag- 
netic field to set the material's 
magnetic polarity. When the 
heated spot cools, the new polar- 
ity is "locked in" and, thus, the 
digital data are recorded. 

Sony's Mini Disc has a couple 
of advantages over other optical 
recording methods. The struc- 
ture of the head is much simpler 
because the laser can be on con- 
tinuously during recording and 
playback. And the low-coercivity 
of the magnetic material greatly 
reduces the power required, 
making portable operation feasi- 
ble. 

One feature of Mini Disc touted 
by Sony is that the portable Walk- 
man players will have "shock- 
proof memory. " One of the prob- 
lems with current portable CD 
players is that they don't work 
too well unless they're standing 
still. Any sharp jarring causes 
the laser to mistrack. Mini Disc 
players shouldn't suffer from 
that problem because data is read 
off the disc at a rate far faster 
than required by the ATRAC de- 
coder, creating a data buffer of 



MINI DISC 




1.4 MBIT/SECOND- 



-L 



^ 



A 



OPTICAL PICKUP 



1 MBIT MEMORY 

~a second CAPAcmt 



0.3 MBIT/SECOND 
_ I I l DIGITAL MUSIC DATA 

[DECODER \ □ ANALOG MUSIC 

L< | SIGNAL 




SHOCK-PROOF MEMORY promises to 
make Mini Disc an ideal portable format. 
Since the data is read off the disc far faster 
than required by the ATRAC decoder, a 
butter as long as three seconds Is created. 

three seconds. If the laser mis- 
tracks, the listener won't hear it. 
The buffer will feed data to the 
decoder while the laser finds its 
way back to the right spot. Sony's 
announcement included a dem- 
onstration where a prototype 
player was shaken vigorously 
without any audible result. The 
prototype continued to play even 
after the disc was removed until 
the 1-megabit buffer was empty! 
Of course, there's no tech- 



nological reason why portable CD 
players couldn't offer their own 
shock-proof memory buffer. But 
since the buffer would have to be 
5 times the size, it would add 
greatly to the cost. 

Who wine? 

Ever since we forecast that DAT 
would be a sure-fire success, 
we've been reluctant to make pre- 
dictions. But let's look at some of 
the issues involved, and how 
DCC and MD stack up. 

For consumers — assuming 
that both formats offer high- 
quality audio — -DCC has the de- 
cided advantage in that existing 
libraries of cassettes won't be ob- 
solete. Both formats have the po- 
tential to supply such con- 
venience features as song title 
and lyric readouts, but MD offers 
much faster random access of 
tracks Although it's too early to 
say for sure, prices for home DCC 
decks should be under $500 
when introduced, while a porta- 
ble MD player is expected to cost 
around $400. For consumers, we 
give DCC a slight edge. 

The recording companies will 
have a hard time taking sides. 
Both technologies will use the se- 
rial copy management system or 
SCMS, an anti-piracy system. 
Manufacturers will be able to du- 
plicate DCC at 64 times normal 
speed on equipment similar to 
what is now used for standard 
cassettes. Mini Disc players will 
be able to play back not only mag- 
neto-optical discs, but pre-re- 
corded optical discs as well — 
discs manufactured using the 
same process as is used for CD's. 
Various recording companies 
have expressed support for each 
format. Which way will the record 
companies go? For us, it's too 
close to call. 

Hardware manufacturers 
should prefer DCC because stan- 
dard tape transports can be 
used. Retailers, always reluctant 
to have to stock the same titles in 
various formats, are dreading the 
thought of re-vamping their 
stores to accommodate either 
DCC or MD. 

What about you? In the long 
run — since both formats seem 
destined to compete with each 
other for your money — it's you 
who will decide whether DCC or 
MD is the personal recording for- 
mat of the 90's and beyond. R-E 



66 




EEEEZiaffiEi 




Driving inductive loads, more on phone caller ID, 

Bakerizing and laminating, alternators as stepper motors, 

and programmable logic resources. 



DON LANCASTER 



Let us first pick up on several 
updates to some of our earlier 
Hardware Hacker topics. One 
good source for those BA1404 FM 
stereo broadcasting kits is DC Elec- 
tronics. They also stock the super 
new Signetics NE602 mixer/convert- 
er chips and the TEC-200 film for di- 
rect toner printed circuits. Another 
NE602 source is Active Electronics. 

Telephone caller ID is certainly one 
hot topic these days. And yet another 
source of call identifier magic boxes 
is Hello Direct. Prices start at $60. 
You must, of course, have the ID ser- 
vice available before you can use 
these magic boxes. States that have 
at least some local availability of caller 
!D should now include AL, CA, FL. 
GA, IL, IN, MD, ME, Ml, NC, NE, NJ. 
NV, OH, OK, SO TN, VA. VT, VW. 
and Washington DC. Other areas are 
Still in the planning stages. Most ser- 
vices are still for local calls only. 

One handy and rather non-obvious 
benefit of this new service: When you 
come back from lunch, you have a 
complete and time-stamped list of ev- 
eryone who tried to call you when you 
were out. Most useful. 

I thought we might round up a big 
collection of odds and ends for this 
month's column... 

Driving inductive loads 

If you blindly connect a transistor 
or another solid-state device to an 
inductor such as a relay or a motor 
coil, you will almost certainly blow out 
your circuit the very first time you 
power it up. Special protection tech- 
niques are always needed when you 
try to control an inductor's current 
with any solid-state device. These in- 
ductive-circuit protection techniques 
are cheap and simple, but you do 
have to understand what is coming 
down to use them properly. 

Take a coil of wire and connect it to 
a voltmeter. Now shove a magnet 
through the center of your coil. As 
you insert the magnet, you generate 
a positive induction voltage. Remove 



the magnet, and you'll generate a 
negative induction voltage. Any time 
your magnetic field changes, you 
generate an induced voltage. And the 
faster the change, the more voltage 
you create. 

Since any current through a coil 
can generate a magnetic field, any 
change in your coil current should 
produce a change in the magnetic 
field, which in turn induces a voltage 
spike. The greater or the more sud- 
den the change in the current, the 
greater the induced voltage. The 
basic math here says that: 

e = LAi/At 

or, in plain English, your induced volt- 
age across any coil is proportional to 
the size of the inductorand the rate of 
change of current through the coil. 

Say you decide to control a relay. 
You turn your relay on by sending a 
current through your coil. And then 
you attempt to turn your relay off by 
suddenly disconnecting your coil cur- 
rent. What happens? 

Your magnetic field will suddenly 
collapse, generating a horrendous 
voltage spike. You tried to make At 
zero, and, since you're now trying to 
divide by zero, you get a theoretically 
infinite voltage spike. Thus, suddenly 
ceasing the current in any inductance 
is guaranteed to create a humongous 
voltage spike. 

Sometimes you might choose to 
purposely do that. For instance, the 
current through the coil in any car 
ignition is suddenly broken to step up 
the 12-volt battery into many tens of 



NEED HELP? 



Phone or write your Hardware 
Hacker questions directly to: 

Don Lancaster 

Synergetics 

Box 809 

Thatcher, AZ 85552 

(602) 428-4073 



thousands of volts of ignition-spark 
voltage. And a related technique gets 
used for television high-voltage. 

But. should you suddenly cease a 
current through any coil in any solid- 
state circuit, the voltage spike you'll 
get is almost certain to blow up the 
transistor of whatever happens to be 
controlling your coil. 

The rule here is simple: Never let 
the current through an inductive load 
suddenly drop to zero in any solid- 
state circuit! 

Figure 1 shows you how to add a 
plain old power diode to your relay 
coil to provide spike protection. Note 
that the diode appears "backward" 
so that it does nor normally conduct 
any supply current. 

If you suddenly try to turn off the 
inductor current, a small induced volt- 
age will immediately be created that, 
in turn, forward biases and turns on 
the protection diode. The current you 
had before can then continue on 
through your protection diode and 
back into the relay coil. The current 
will now drop down to zero fairly 
quickly, dissipating itself in the for- 
ward drop of the diode and in the 
internal resistance of your relay coil. 
At no time is any voltage spike gener- 
ated that exceeds the 0.6 volts or so 
of your diode's forward drop. 

This simple diode despiker works 
quite well. But there are some minor 
side effects that can sometimes 
cause problems. Note that your relay 
will stay pulled in for a brief time delay 
after you thought you turned if off. 
That happens because there is still 
diode- provided current going through 
your coil. In a larger relay, the time 
delay could extend a few tenths of a 
second, and could cause you timing 
problems. 

The physical dropout of your relay „ 
can also end up slower and sloppier. ^ 
Which could cause contact arcing in m 
higher-current uses. § 

Your protection diode should also 3 
turn on fairly fast. If you use a slow ^ 
diode, or if there is not enough stray iS 



67 



INDUCTIVE 
LOAD 



[0-W1V 



± DESPIKING 
DIODE 



INDUCTIVE 
LOAD 



Hp 



FIG. 1— ANY SEMICONDUCTOR can be in- 
stantly destroyed if you use it to suddenly 
turn off the current in an inductive load. 
The despiking diode shown here allows 
the coil current to continue long enough 
to safely dump the magnetic flux energy 
without creating a killer transient. 



circuit capacitance around, a large 
and possibly destructive spike can 
build up during the time your diode 
actually starts conducting. 

Figure 2 shows you an improved 
spike-protection circuit. Here we 
have added a 24-voit Zener diode in 
series with the protection diode. This 
combination will conduct no current 
in one direction and will conduct in 
the other direction only when the volt- 
age across it exceeds the Zener 
breakdown of 24 volts. You can think 



NEW FROM 

DON LANCASTER 



HARDWARE HACKER STUFF 





Hardware Hacker Reprints II or II] 


24.50 




Midnight Engineering Reprints 


16.50 




Incredtble Secret Money Machine 


12.50 




CMOS Cookbook 


24.50 




TTL Cookbook 


19.50 




Active Filter Cookbook 


19.50 




Micro Cookbook vol 1 or II 


19.50 




Lancaster Classics Library 


109.50 




Enhancing your Apple 1 or II 


17.50 




AppleWriter Cookbook 


19.50 




Absolute Reset He & He 


19.50 




Enhance 1 or II Companion Disk 


19.50 




AppleWriter CB or Assy CB Disk 


24.50 




POSTSCRIPT STUFF 






Ask The Guru Reprints 1, II or III 


24.50 




LaserWriter Secrets (lle/Mac/PC) 


29.50 




PostScript Show & Tell 


39.50 




Intro to PostScript VHS Video 


39.50 




PostScript Beginner Stuff 


39.50 




PostScript Cookbook (Adobe) 


16,50 




PostScript Ret. Manual 11 (Adobe) 


28.50 




PostScript Program Design (Adobe 


22.50 




Type 1 Font Format (Adobe) 


15.50 




LaserWriter Reference (Apple) 


19.50 




Real World Postscript (Roth) 


22.50 


en 


PostScript Visual Approach (Smith; 


22.50 


O 


Thinking in PostScript (Reid) 


22.50 


z 

o 


The Whole Works (all PostScript) 


299.50 


rr 
o 


FREE VOICE HELPLINE VISAfMC 


ill 


SYNERGETICS 


LU 

6 

Q 
< 


Box 809-RE 




Thatcher, AZ 85552 


(602) 428-4073 





DESPIKING 
DIODE 

ENERGY- 
DUMPING 
ZENER 



INDUCTIVE 
LOAD 



[^o-JyWV- 



-§ 



FIG. 2— ADDING A SERIES Zener diode 
shortens and sharpens the dropout time. 
This minimizes turn-off delay and contact 
arcing in power relays. Your control tran- 
sistor must be able to block the supply 
voltage PLUS the Zener voltage. 

of this series combo as an "inefficient 
diode" with a 24-volt forward drop. 

Whenever you suddenly discon- 
nect your relay current, a large but 
acceptable 24-volt high-voltage spike 
is created, which turns on both di- 
odes in the series pair. The current 
continues through the diodes, but will 
fall to zero much faster as you now 
have a 24-volt drop burning up all of 
your remaining coil energy. Thus, the 
circuit will still give you protection, but 
will shorten the excess holding time 
by a factor of 40 or so. Your contact 
release will also be that much faster. 

What happens is that you've now 
made a tradeoff. You are allowing a 
reasonably sized spike in exchange 
for a big reduction of the release time. 
Note that your transistor will see a 
maximum voltage of your supply volt- 
age plus the drop of the Zener during 
break time. For instance, on a 12-volt 
supply, your transistor would have to 
block at least 36 volts if it is not to be 
damaged. 

There are special back-to-back 
Zener-like components intended for 
spike protection. They go by the 
names of varistors, MOV's, or 
transient protectors, and do have 
various brand names. They work the 
same way as Fig. 2 in that they do not 
conduct until spike time. Then they 
do conduct heavily and internally dis- 
sipate the inductor's flux energy. Fig- 
ure 3 is a typical circuit. 

SGS is one of many suppliers of 
the TRANSIL spike protectors. Their 
BZW04P23 is typical. At 25 volts or 
under, it draws only 5 microamps. 
Above 30 volts it starts conducting 
heavily, and by 41 .5 volts it draws at 
least 10 amperes. Despite the tiny 
package, these devices can with- 
stand 50 amps for 10 milliseconds. 
Higher-power units are also available. 



A 



TRANSIENT 
PROTECTOR 



o-W/t- 



FIG. 3— TRANSIENT SUPPRESSORS are 
commercially available bi-directional de- 
vices that are also known as varistors, 
MOV's, TRANSILS, or several other trade 
names. These must be carefully matched 
to the allowable voltage rise and the mag- 
netic flux energy to be dumped. 



You do have to carefully match your 
protection device to the size of the 
spike you are willing to allow and the 
amount of energy that you need to 
dump from your coil. If at all possible, 
you should also isolate your coil driv- 
ers from more sensitive parts of your 
circuit. Optoisolators and individual 
power supplies are great for this. 
More info on spike protection and 
computer interfacing appears in my 
Micro Cookbook, volume II. 

Alternators as steppers? 

A stepper motor differs from an 
ordinary motor in that it can deliver 
incremental motion in the form of tiny 
precise steps, rather than as a contin- 
uous rotation. The important advan- 
tages of a stepper motor are the 
precision with which you can set an 
output shaft position, the ability to 
rapidly and conveniently change the 
direction or the speed of your output 
steps, and the capability of strongly 
holding a zero-speed position. 

Small stepping motors are widely 
used for such things as printer paper 
feeds, automobile idle controls, pen 
plotters, and sometimes for disk- 
drive head positioners. And most any 
old surplus electronics catalog will 
have lots of small steppers and all 
their drivers cheaply available. But 
what about the heavy stuff? 

There are lots of good hacking 
uses for power stepper motors. Ob- 
vious examples include robotics, ma- 
chine-tool power feeds, animation 
stands, plotters, sign cutters, solar 
pumps, and even Santa Glaus ma- 
chines. As you have probably noticed 
by now, power stepper motors are 
rare, horrendously expensive, hard to 
get, and harder to drive. Did I mention 
being hot and noisy? 



68 



An industrial arts teacher out of 
Phoenix by the name of Bob Knight 
stopped in the other day with what 
just might be a brilliant hack. 
Junkyard car alternators cost under 
$5 each, especially if you don't par- 
ticularly care which model you are 
getting. Can you convert an alter- 
nator into a power stepper? 

The needed modifications do ap- 
pear to be simple and obvious. And 
power FET or Darlington drivers are 
no big deal these days. 

My first response was "yes, 
but...," and I immediately came up 
with a dozen good reasons why this 
flat out would not work. At least not 
very well. Things like a wide air gap, 
low-frequency mechanical reso- 
nances. DC biasing, giant step sizes. 
all the non-optimum magnetic paths, 
very poor damping, backlash, slow 
speeds, and an efficiency that proba- 
bly would be an outright joke. 

On the other hand, if you pulse an 
alternator, there is no way you can 
hold onto it when you do. The kick is 
definitely there. 

At best, I would guess that you 
could not get as much useful force 
with a car alternator as you could by 
using a much smaller "real" stepper 
motor. And the alternator would end 
up ridiculously slower to boot. 

I'd like you to try and prove me 
wrong. Either as this month's contest 
or for a winning school lab project, 
experiment with a car alternator and 
find out exactly how useful a power 
stepper motor you could convert it 
into. Could you in fact create a $5 
machine-tool power feed with one? 
How fast can you go? How much out- 
put force can you get? How good are 
the steps? What is the best computer 
interface? 

There will be the dozen or so of our 
usual Incredible Secret Money Ma- 
chine book prizes, along with a big all- 
expense-paid (FOB Thatcher, AZ) 
tinaja quest for two going to the very 
best of all. 

Okay, Fig. 4 shows you some con- 
version hints. 

Most real stepper motors do use a 
permanent magnet rotor. With an al- 
ternator, you would use the field 
winding and slip rings as a giant elec- 
tromagnet, running as much current 
through it as you can without over- 
heating. This forms a group of seven 
shaft-attached magnets that you can 
rotate to a desired position by activat- 
ing the stator coils. 



+12 voc 
o 



STATOR A 



MODIFIED CAR ALTERNATOR 



^ 



STATOR 6 STATOR C 



ROTOR 




1_ 



5O..10W 5 5O.10W 





5D,10W 



3Ii.10W 



Silicon power transistors, 
Power Darlingtons, 
or Power FETs 



FIG. 4 — CAN A CAR ALTERNATOR get converted into a S5 power stepper for a machine 
tool drive? Only hackers know for sure. To experiment, use the rotor as a powerec 
electromagnet. Find the floating stator wye connection and bring it out as a power 
terminal. Pulse one stator winding at a time in an ABC (clockwise) or an ACB (coun- 
terclockwise) sequence. Be sure to limit stator currents. 



And speaking of which, there are 
normally three sets of stator coils. 
These are usually hooked up in what 
is known as a three-phase wye cir- 
cuit. For stepper use, you will want to 
find the floating splice where your 
wye connection is made and bring it 



out as a separate positive terminal. 
Which should then give you three dis- 
tinct and independent winding sets. 
Let's call the windings A, B, and C, 
Power the field via the slip rings, and 
pulse winding A. Keep your current 
down around an amp or two at first to 



BAKERIZING 



With BAKERIZING, your toner image is 
temporarily placed in close contact with 
a smooth film. Heat and pressure is then 
applied. The toner becomes much blacker 
and takes on a beautiful medium to high 
gloss. Some films can be reused. 



LAMINATING 



With LAMINATING, a thin clear plastic 
overlay is permanently attached to your 
copy by using heat and pressure. This 
process seems ideal for menus and book 
covers, or where extreme scuff resistance 
to "lock in" your toner is required. 



u 



FIG. 5 — THESE TWO "MAGIC" FILMS can dramatically improve the appearance and 
durability of any toner image. Evaluation sheets are newly available. 



w 

m 

| 

m 

rr 

x 



ID 

as 



69 



prevent any overheating or driver 
problems. The rotor will align itself 
with the nearest pole piece and 
should lock itself to some position. 
Now turn off winding A and activate 
winding B. The rotor should nowjump 
one step clockwise. Turn off B and 
whap C. And you should jump yet 
another step clockwise. 

To step clockwise, use an ABC se- 
quence. To step counterclockwise, 
just use ACB instead. You'll probably 
want to keep at least one winding 
energized at all times so that you can 
hold a position when not stepping. 

Note that you could end up in posi- 
tion A, B, or C. depending on your 
power sequence. You'll have to re- 
member where you are with your con- 
troller or host computer, A typical 
alternatorshouldgiveyou21 possible 
positions, and a resultant step angle 
of around 17 degrees. 

You would disconnect all of the al- 
ternator diodes during your con- 
version. These could later get used 
as protection diodes with your driver 
circuits if you do not have anything 
better available. 

One hint: Your slip ring brushes 
can "explode" whenever you take an 
alternator apart. And the two brush 
springs will fly off into the hinterlands. 
Look closely, and you'll fipd a tooth- 
pick-size hole in the insulated brush 
holders. To reassemble, you just put a 
toothpick or a stiff wire through the 
hole to hold the brush springs com- 
pressed. Done just right, you should 
be able to remove the toothpick from 
the outside after your reassembly. 

The rotor winding of an alternator is 
a fairly high resistance, usually 
around 5 ohms or so. It will safely 
current limit itself. But your stator 
windings are an extremely low imped- 
ance, typically under a quarter ohm. 
Thus, you must externally limit your 
rotor currents to keep things from 
burning up. Plain old power resistors 
are a good way to handle this for your 
early experiments. 

There are some tricks you could 
pull to improve the number of steps 
per revolution. One would be to allow 
two windings to be active at once. 
That could double your resolution. 

A fancier technique would be to 
allow several different values of the 
current for each winding, leading to 
various new microstepping oppor- 
tunities. Microstepping is a proven 
concept with real stepper motors. 

Another possibility is to use a 



Active Electronics 

11 Cummtngs Pk 
Woburn MA 01801 
(800) 677-8899 

CIRCLE 301 ON FREE INFORMATION CARD 



NAMES AND NUMBERS 

Photocomm, Inc 

7681 East Gray Road 
Scottsdale, AZ 85260 
(800) 223-9580 

CIRCLE 309 ON FREE INFORMATION CARD 



Alrpax 

150 Knotter Drive 
Cheshire, CT 06410 
(203) 271-6000 
CIRCLE 302 ON FREE INFORMATION CARD 

DC Electronics 

PO Box 3203 
Scottsdale, AZ 85271 
(800) 423-0070 

CIRCLE 303 ON FREE INFORMATION CARD 

Galco 

26010 Pinehurst Dr 
Madison Heights Ml 48071 
(313) 542-9090 
CIRCLE 304 ON FREE INFORMATION CARD 

Hello Direct 

140 Great Oaks Blvd 
San Jose, CA 95119 
(800) 444-3556 
CIRCLE 305 ON FREE INFORMATION CARD 

Maxim 

120 San Gabriel Drive 
Sunnyvale, CA 94086 
(408) 737-7600 

CIRCLE 306 ON FREE INFORMATION CARD 

Memory Card Systems & Design 

6300 S Syracuse Way, Ste 650 
Engiewood, CO 80111 
(303) 220-0600 
CIRCLE 307 ON FREE INFORMATION CARD 

Motorola 

5005 East McDowell Road 
Phoenix, AZ 85008 
(800) 521-6274 

CIRCLE 306 ON FREE INFORMATION CARD 



bridge-type drive that lets you run cur- 
rent either way through any given 
winding. You could now use both at- 
traction and repulsion, and, once 
again, should be able to double the 
number of steps. 

And a final resolution enhancer 
would be to put a nutplate of some 
sort on the shaft end. creating a linear 
stepper. A threaded shaft through the 
nutplate will then move forward or 
backward as the alternator steps. 

For instance, with a '/4-20 thread, 
each full revolution would advance 
you fifty mils. One single step at 21 
steps per revolution would advance 
you a mere 2.38 mils, besides giving 
you a really major mechanical advan- 
tage to boot. 

Simple gearing could also be used 



Rochester Electronics 
10 Malcolm Hoyt Drive 
Newburyport, MA 01950 
(508) 462-9332 

CIRCLE 310 ON FREE INFORMATION CARD 

SGS-Thomson 

100 East Bell Road 
Phoenix, AZ 85022 

(602) 867-6259 

CIRCLE 311 ON FREE INFORMATION CARD 

Slo-Syn 

383 Middle Street 
Bristol, CT 06010 
(203) 582-9561 

CIRCLE 312 ON FREE INFORMATION CARD 

Sp rag ue 

70 Pembroke Road 
Concord, NH 03301 

(603) 224-1961 

CIRCLE 313 ON FREE INFORMATION CARD 

Synergetics 

Box 809-RE 
Thatcher, AZ 85552 
(602) 428-4073 

CIRCLE 314 ON FREE INFORMATION CARD 

Trade winners 

PO Box 7-250 
Taipei, Taiwan, ROC 
(02) 733-3988 

CIRCLE 31S ON FREE INFORMATION CARD 

JC Whitney 

1917-19 Archer Avenue 
Chicago, IL 60680 
(312) 431-6102 

CIRCLE 316 ON FREE INFORMATION CARD 



to increase your step resolution. But 
you will have to watch for backlash 
when you try this. And do note that 
the finer the resolution, the slower 
your maximum allowable operating 
speed. Sorry about that. 

You might also like to look at some 
dual current scheme that gives you a 
brief high-current pulse when step- 
ping and some lower holding current 
between the actual steps. 

After you do have your stepper 
working reasonably well, you'll want 
to increase the operating currents. 
Overheating, saturation effects, and 
overshoots set your ultimate limit. 

It might also be very interesting to 
rewind all the stator coils. Use lots 
more turns of a much smaller-diame- 
ter wire, and try bridging only a single 



70 



PROGRAMMABLE LOGIC RESOURCES 

Actel Mitsubishi 

955 East Arques Avenue 1050 East Arques Avenue 

Sunnyvale, CA 94086 Sunnyvale, CA 94086 

(800) 227-1817, ext. 60 {408) 730-5900, ext. 2106 

CIRCLE 317 ON FREE INFORMATION CARD CIRCLE 327 ON FREE INFORMATION CARD 



Altera 

2610 Orchard Parkway 
San Jose, CA 95134 
(800) 800-EPLD 

CIRCLE 318 ON FREE INFORMATION CARD 

Advanced Micro Devices 

PO Box 3453 
Sunnyvale, CA 94088 
(800) 222-9323 
CIRCLE 319 ON FREE INFORMATION CARD 

Catalyst 

2231 Calle de Luna 
Santa Clara, CA 95054 
(408) 748-7700 
CIRCLE 320 ON FREE INFORMATION CARD 

Cypress Semiconductor 
3901 North First Street 
San Jose, CA 95134 
(800) 952-6300 Dept. C4P 

CIRCLE 321 ON FREE INFORMATION CARD 

Fujitsu 

3545 North First Street 
San Jose, CA 95134 
(800) 642-7616 

CIRCLE 322 ON FREE INFORMATION CARD 

Gould AMI Semiconductor 

2300 Buckskin Road 
Pocatello, ID 83201 
(208) 234-6668 

CIRCLE 323 ON FREE INFORMATION CARD 

International CMOS Technology 

2125 lundy Avenue 
San Jose, CA 95134 
(408) 434-0678 
CIRCLE 324 ON FREE INFORMATION CARD 

Intel 

1000 Business Center Drive 
Mt. Prospect, IL 60056 
(800) 548-4725 
CIRCLE 325 ON FREE INFORMATION CARD 

Lattice Semiconductor 

5555 NE Moore Court 
Hillsboro, OR 97124 
(800) FAST-GAL 

CIRCLE 326 ON FREE INFORMATION CARD 



stator pole rather than three. Ampere 
turns is the name of the game here. 
You could also try improving the rotor 
flux paths and air gaps. 

For further resources on power 
stepping in general, check out Airpax 
and Sio-Syn for iron, the POM and 
Motion trade journals for info, and 
SCS, Sprague, or else Motorola for 
drivers. One distributor that stocks a 



National Semiconductor 

2900 Semiconductor Drive 
Santa Clara, CA 95051 
(800) 272-9959, ext. 40 

CIRCLE 328 ON FREE INFORMATION CARD 

NEC Corporation 

401 Ellis Street 
Mountain View, CA 94039 
(415)965-6000, ext. 6357 

CIRCLE 329 ON FREE INFORMATION CARD 

GEC Plessey Semiconductor 

13900 Alton Parkway, S 123 
Irvine, CA 92718 
(800) 927-2772 
CIRCLE 330 ON FREE INFORMATION CARD 



Raytheon 
350 Ellis Street 
Mountain View, CA 94039 
(415) 962-7930 
CIRCLE 331 ON FREE INFORMATION CARD 

Texas Instruments 

PO Box 117692 
Carroliton, TX 75011 
(800) 336-5236. ext. 3707 

CIRCLE 332 ON FREE INFORMATION CARD 

Toshiba 

1220 Midas way 
Sunnyvale, CA 94086 
(800) 321-1718 

CIRCLE 333 ON FREE INFORMATION CARD 

Waferscale Integration 

47280 Kato Road 
Fremont, CA 94538 
(415) 656-5400 

CIRCLE 334 ON FREE INFORMATION CARD 

Xicor 

1511 Buckeye Drive 
Milpitas, CA 95035 
(408) 432-8888 
CIRCLE 335 ON FREE INFORMATION CARD 

Xilinx 

2100 Logic Drive 
San Jose, CA 95124 
(408) 879-5199 
CIRCLE 336 ON FREE INFORMATION CARD 



wide selection of power-electronics 
stuff is Galco. And good old J.C. 
Whitney has bunches of alternators 
and parts available, including some 
rewound 100-amp stators that go for 
around $18. You will find lots more on 
power electronics in our brand new 
Hardware Hacker ill reprints. There's 
lots of possibilities here. Let's see 
what you can come up with. 



Programmable logic 

Besides all those good old hacker 
EPROM's, we now have dozens of 
variations on low-cost you-program 
integrated circuits. Some (such as 
EPROM's) are based on exhaustive 
table lookups. While others (such as 
PLA's) do multilevel and on digital log- 
ic using combinations of gates and 
registers. 

Some are one-shot programmed 
by blowing fuses. Others are easily 
re-programmable. And yet others use 
a flash technology where the needed 
connections can get saved to a non- 
volatile RAM memory during power- 
down times. 

The prices of some programmable 
chips are now down in the $2 range. 
Important advantages of these new 
devices are that you can place the 
exact circuit you want into one or two 
packages; that they are easy to de- 
bug and modify yourself; that some 
can recalibrate or update themselves 
later on in-circuit; and that you are (at 
least temporarily) the sole source of 
your "secret" inside programming 
connections. All with instant delivery 
and no staggering setup charges. 

I've tried to gather together some 
of the more popular programmable 
logic suppliers into this month's re- 
source sidebar. You may want to get 
data from many of these sources. 

One side note that is both alarming 
and sad: Many of these houses re- 
fuse to divulge the key programming 
info needed to use their chips. While I 
consider this a monumentally stupid 
way to cut off your nose to spite your 
face, their argument is that they most 
definitely do want you to use some 
"approved" programmer that is more 
likely to keep their products reliable in 
the final circuit. 

Here's a trick that may help you get 
programming info should reasonable 
and direct tries fail. The magic new 
buzzword in chip programmers these 
days is "DAC per pin." Just tell those 
application engineering people that 
you are about to ship production 
quantities of your new PC-based 
DAC-per-pin programmer, and that 
you would like to be able to include 
pro-grammability for their chips. 

Our helpline has been full of horror 
stories on programming info, but this 
ploy seems to work so far. At least till 
they catch on. Please do continue to 
send in your horrors stories. 

More details on the use of 
EPROM's appears in my CMOS 



GO 

m 
-0 



- 
m 



to 
to 



71 



m 
O 

2 

o 

CC 



I,EARI\ 



VCR 

REPAIR TECHNIQUES 




Now, in a complete multimedia package 
consisting of a 200- page training manual and 
a 1-hour 22-minute video training tape, you 
can leam secrets of Advanced VCR Repair. 
(Also includes Color Bar Test Tape.) 

Indudesmany exam pies of VC R make/model 
specific troubleshooting tips . . . Learn how to 
quickly isolate most "tough" VCR malfunc- 
tions, whether electrical or mechanical. 

Complete coverage of Theory of Operation 
— Read manual, view 1-hour 22-minute 
video I 

FREE INFORMATION PACKAGEl 

Call 1/800-537-0539 

Viejo Publications, Inc. 

5329 Fountain Ave., Dept. REA 

Los Angeles, CA 90029 



CIRCLE 179 ON FREE INFORMATION CARD 



Shortwave Listening 
Guidebook 



by Harry Helms 

The world is talking on shortwave radio, 
and here's the book that tells you how to 
listen in! In direct, nontechnical language, 
Harry explains how to get the most from 
your shortwave radio. Its 320 heavily 
illustrated pages are filled with practical 
advice on: 

• antennas 

• when and where to tune 

• selecting the right radio for you 

• accessories 

• reception techniques 

Leam how to hear 
the BBC. Radio 
Moscow, ham radio 
operators, ships at 
sea, even Air Force 
One! Includes 
hundreds of 
frequencies for 
stations around the 
world and the times 
you can hear them. 




frj Only $16.95 plus 



LU 

6 

D 
< 

tr 
72 



vniy$10.H2pius T y 1 r~w-t 

$3. 00 shipping J^ I CrJlIeX t 

(CA residents D p a b 1 1 nn I ku . i ne. 



(CA 

please include 

sales tax). 



' Pub 

7128 Miramor Rood 
Suite 15L. San DioG.il, CA 82121 



Cookbook and TTL Cookbook, while 
the listings in our resource sidebar 
and the usual trade journals will also 
have lots of application info. 

Bakerizing secrets 

Despite my screaming it from the 
rooftops for quite a fow yea re now, 
Bakerizing seems to remain a top- 
secret procedure. Which amazes me 
because anyone that sees what the 
process does is absolutely stunned. 

Bakerizing is a sneaky trick you can 
apply to most any toner image, es- 
pecially all your PostScript laser- 
printed output. Bakerizing instantly 
makes toner a high-gloss jet black, 
while at the same time dramatically 
increasing the durability and crease- 
resistance. 

While excellent for business cards, 
Bakerizing works nearly anywhere 
that you want a blacker and denser 
toner image. And the process is near- 
ly free! 

All you have to do to Bakerize is 
take a sheet of special high-gloss, 
slip-coated polyester film. You then 
temporarily place the film in contact 
with your toner image and then apply 
heat and pressure. This remelts your 
toner in contact with an ultra-smooth 
surface. Which then can produce a 
catandering process similar to that 
ferrotype drum on older darkroom 
glossy print processors. 

The simplest way to Bakerize is to 
put the magic sheet on top of your 
hard copy and shove it back through 
your printer while imaging a blank 
page. The best way to Bakerize is to 
use a Kroy Color or Canon fuser unit 
or some sort of laminating machine. 
But even a plain old iron can some- 
times be used effectively. 

With care, any single Bakerizing 
sheet can be reused dozens of times. 
Which can drop your per-page costs 
to a few pennies per copy. 

I have gone ahead and custom or- 
dered a zillion sheets of Bakerizing 
film and will be offering it as a stock 
product here at Synergetics, I've also 
now got some more traditional yet 
toner-compatible laminating materi- 
als suitable for nice looking menus 
and book covers. Figure 5 shows you 
how these two films differ. Give me a 
call if you want to play with either of 
these really exciting new materials. 

New tech lit 

From SGS, the new Shortform 91 
catalog that is especially strong in 



automotive, telephone, VCR, and 
consumer audio chips. From 
Rochester Electronics, a 1991 Cata- 
log. They specialize in stocking many 
types of out-of-date and discontinued 
semiconductors. 

A free design guide and catalog on 
Solar Electric Power Systems from 
Photocomm inc. is now available. 
And the latest free volume of the 
Maxim Engineering Journal has all 
sorts of goodies in it on efficient reg- 
ulators, digital filters, and other inno- 
vative new chips. 

Two informative trade journals for 
this month do include Memory Card 
Systems & Design on the new RAM 
and EPROM memory cards used for 
laptops and whatever: and Trade Win- 
ners. The latter journal is sort of a 
Hong Kong version of Computer 
Shopper that can give you direct ac- 
cess to many Far East manufacturers 
and distributors of electronic parts 
and systems. 

Let's see. I've just reprinted my 
Incredible Secret Money Machine. 
along with a new introduction and up- 
date section. And we are now Book- 
on-demand publishing our Hardware 
Hacker III, Ask the Guru lit, and also 
my Midnight Engineering I reprints. 

A reminder about my new BBS up 
as GEnie PSRT. Besides all of the 
PostScript and desktop publishing 
stuff, you'll find all sorts of ongoing 
Hardware Hacker and our Midnight 
Engineering resources here. You can 
get your voice connect info by dialing 
(800) 638-9636. 

Finally, I do have a pair of new and 
free mailers for you. One includes 
dozens of insider hardware hacking 
secret resources, while the other is 
on PostScript and Desktop Publish- 
ing, Write or call for info. As usual, 
most of the items mentioned here 
appear in the Names and Numbers or 
the Programmable Logic Resources 
sidebars. r-e 




Fve hetirtl you were iovkitix for me . . . Super 
amtluctvr? 



Computer 


Viruses 




jgf ! >c^kt' 


tfft 





3382 P S2935 
Counts as 2 




INTEL'S 

OFFICIAL GUIDE TO 

386 

COMPUTING! 



H1G93-9P S29.9S 



1 l/V» 










9372P I21.9S 
Countt At 3 


3951 P S18.9E 


— 


^ - 


JjaSyMJatog'^ 


PM0UMUMC 


M 




BB 


. . ' 


■ 



35-25P 821,95 




SELECT 3 BOOKS 
for only $ 4^ 




The Computer Book Club and the BYTE Book Club have 

joined forces to bring you the largest selection of business 

and personal computing titles available ... at savings 

up to 50% off publishers' prices! 

tvtvtvtvt Membership Benefits ▼vtvtww 

• Big Savings In addition to this introductory offer, you keep saving substan- 
tially with members' prices of up to 50% off the publishers' prices. 

• Bonus Books Starting Immediately, you will be eligible for our Bonus Book 
Plan, with savings of up to 80% off publishers* prices. 

• Club News Bulletins 15 times per year you will receive the Book Club News, 
describing all the current selections— mains, alternates, extras— plus bonus of- 
fers and special sales, with scores of titles to choose from. 

• Automatic Order If you want the Main Selection, do nothing and it will be 
sent to you automatically. If you prefer another selection, or no book at all, simply 
indicate your choice on the reply form provided. You will have at least 10 days 
to decide. As a member, you agree to purchase at least 3 books within the next 
2 years and may resign at any time thereafter. 

• Ironclad No-Risk Guarantee If not satisfied with your books, return them 
within 10 days without obligation! 

• Exceptional Quality All books are quality publishers' editions especially 
selected by our Editorial Board. 

All books »ra hRrfcow unlesi number it lolkrwod by a "P" lor papafbMk. (Publifljwti" PficM Shown) 
C18S1 THE COMPUTER BOOK CLUB. Blue Hidg* Summit. PA 172944620 

FREE when you join! 

Hard Disk Management: 

The Pocket Reference: by Kris Jamsa 

Make the most of your hard disk's ^ 

capabilities with this pocket reference. ( S5.95 
Find out how to back up files, organize V Value; 
your disk for peak performance and more 



r- 



i 



The Computer Book Club 




Mi Its snE Soot CtulT 



Blua Ridge Summit, PA 17294H3B20 



Please accept my membership in The Computer Book Club with the BYTE Book Club and 
send the 3 volumes listed below. billing me $4.95 plus my tree copy ot Hard Disk Management 
(#88148Q-4P^ If not satisfied, I may return the books within ten days without obligation and 
have my membership cancelled, \ agree to purchase at least 3 books at regular Club prices 
during the next 2 years and may resign any lime thereafter. A shipping/handling charge and 
sales tax will be added to all orders. 



372Q 526.9:5 



150S7P 535.05 
Oeunls it a 



Name . 



Address 
City 



State _ 



_Zip. 



Valid tor new members only, Foreign applicants will receive special orris ring instructions Canada must remtt 
in U.S. currency. This order subject to acceptance by The Computer Book Club HP1C991 




3379P £24.95 

I--.- mblj Loftguas? 
SubroutlnB 
for MS-DOS 



3679P 5112.95 

Iriiru I HI** 
Guaranteed! 



333tp 5H-95 9S49P S2«.9S 



Hie C Primer 




382a S29.95 
Counts as 2 



■mm UMMG 




Kisiun: sik*!«t 

HIUH ■ 1 


1 


£^- 
^ 


! 
] 





3SB3P SSt9S 
Ccurvtt M 3 




m 



m 

SO 
CO 



73 



AUDIO UPDATE 



Future products? 



LARRY KLEIN 



Despite my thirty-plus years as 
an editor and writer for major 
hi-fi magazines, I've always 
been an odd-man out among audio 
journalists. When I saw a develop- 
ment that struck me as a genuine 
advance in the audio-video arts, I was 
pleased to say so. But unlike many, if 
not most, of my colleagues, I never 
felt an obligation to be a knee-jerk 
cheerleader for each new audio con- 
cept, device, or format. Hopefully, 
over the years my approach has 
helped readers find their way through 
the fast-changing and sometimes 
confusing world of audio electronics. 

In-store recording 

Sometimes new developments are 
hard to call. For example, loyal read- 
ers may remember my November 
1988 writeup of the Personics in- 
store tape-it-yourself machine. It per- 
mits consumers to record their own 
top-40 — or whatever — compilations 
at perhaps a buck a shot from its 
thousands of digitally stored mas- 
ters. I was impressed by Personics 
very sophisticated technology, but I 
asked whether it might not be a tech- 
nically feasible idea that, neverthe- 
less, wouldn't get off the ground 
because it didn't dovetail with the per- 
ceived social or economic needs of 
the marketplace. 

My question was recently an- 
swered when Personics filed for 
Chapter 11 bankruptcy protection. It 
seems that although the record 
stores were pleased to install the ma- 
chines, the record companies 
wouldn't provide Personics with a 
sufficient number of their more popu- 
lar selections, despite the fact that 
they earned royalties on every selec- 
ts tion taped. They obviously felt that it 
z would hurt prerecorded cassette and 
§ CD sales. It seemed to me that Per- 
o sonics had made a good case that 
j their machine would help cut back on 
i "illicit" home taping, but the record 
5 companies obviously didn't see it 
S that way. 



Recordable CD's 

A product/format that I ignored 
when it was first introduced was Ra- 
dio Shack's home-recordable com- 
pact-disc system, dubbed "Thor" for 
Tandy High-Intensity Optical record- 
ing. Announced in June 1988, the 
Thor recorder/player was to be 
priced at under $500 and be on the 
market in less than two years. The 
press went wild! Laudatory articles 
appeared in major publications and at 
least one audio columnist predicted 
that it "could well become the domi- 
nant recording method for the next 
several decades." Well, here we are 
three years later, and the product is 
nowhere to be seen. 

A recent call to Radio Shack/Tandy 
revealed that Thor was still in the 
works; it had reached the "product 
development" stage, but Radio 
Shack thought it prudent not to re- 
schedule a release date. In our con- 
versation. I indicated that I saw the 
recordable high-density disc as suit- 
able for computers Ca sort of cheap 
recordable CD-ROM), but I didn't 
see much future for it as a hi-fi medi- 



um. My friend from Radio Shack told 
me that they were working in the op- 
posite direction. A year, or two, or 
three, from now we may know who 
was right. 

Mini discs 

Scheduled to appear sometime in 
late 1991, the Sony Mini Disc system 
uses 2.5-inch record/playback discs 
physically similar to 3.5-inch comput- 
er discs. The MD system uses a 
combination of optical and magnetic 
digital technology; prerecorded discs 
are optically read with a laser, and 
home recording is done using a so- 
phisticated thermal/magnetic sys- 
tem with the laser providing the 
thermal element. Guesttmated intro- 
ductory price is in the $350 range. 

The Mini Discs have a storage ca- 
pacity virtually identical to that of a 
conventional CD, thanks to Sony's 
newly developed digital compression 
system call ATRAC (Adaptive Trans- 
form Acoustic Coding). ATRAC 
works by analyzing the audio signal 
and extracting and encoding only 
those components that are audible to 




DOES SONY'S MINI DISC SYSTEM WITH RECORDABLE DISCS represent the audio 
format of the future? 



74 



the ear. In other words, frequencies 
that would be psychoacousticaJly 
masked by other frequencies are left 
unencoded as are frequencies on the 
loudness scale judged to be below 
the threshold of perception. Although 
the dynamic range of the MD system 
Is given as 105 dB, I wonder if play- 
back through an external home audio 
system will reveal any ATRAC inade- 
quacies. 

In any case. Sony's present plans 
are to concentrate on portable ap- 
plications which are far more forgiv- 
ing of compression artifacts. There 
are several other important tech- 
nological developments incorporated 
into the MD format that are important 
enough to deserve further discus- 
sion, but they are outside the scope 
of this column. 

Ss this Sony's answer to the DCC 
format discussed last month? Well, 
Mr. Norio Ohga, President of the 
Sony Corporation, stated in his pre- 
pared remarks at the Mini Disc press 
conference, that the "sales of pre- 
recorded music cassettes are declin- 
ing, especially in Japan. We have 
investigated the reasons for this de- 
cline, and our own research showed 
that consumers are not totally satis- 
fied with music compact cassettes, 
primarily because of slow access 
time and such problems as wow, flut- 
ter, and distortion." 

I suspect that the fall-off in pre- 
recorded cassette sales has more to 
do with the success of CD than newly 
bothersome flaws in the cassette for- 
mat. When the earlier choice was be- 
tween an LP or a prerecorded 
cassette, the cassette won on the 
basis of convenience and rugged- 
ness. Now that the choice is between 
CD's and cassettes, the CD has the 
edge in convenience and rugged- 
ness — and you can always make your 
own cassette copy to take with you in 
your travels. 

I also differ with Mr. Ohga on the 
importance of the fidelity factor for 
the U.S. mass music market. If 
fidelity was that important to most 
rock music consumers, prerecorded 
cassettes would never have outsold 
LP's — as they did for several years 
before CD's arrived. Is the market- 
place ready for another non-compati- 
ble portable/car format? I wish Sony 
well, and I'm impressed by the tech- 
nology developed for the Mini Disc, 
but I'm not optimistic about its ulti- 
mate success in the marketplace. 



HDTV 

Billed as high fidelity for the eyes, 
high-definition television is a favorite 
topic among Sunday supplement 
magazine writers. Soon, they would 
have us believe, our 30- or 40-inch 
home TV screens will be showing pic- 
tures that, in respect to aspect ratio, 
clarity, and detail, will rival those seen 
in movie houses. Well, don't hold 
your breath — or put off purchasing a 
TV set with today's old fashioned 
technology. HDTV is not just around 
the corner. 

HDTV's major problems are not 
technological — they are economic 
and sociological. To start, the broad- 
casters must transmit separate 
HDTV and standard signals simulta- 
neously in order to comply with the 
FCC's compatibility rule. If they want 
to originate programs, they need new 
cameras, recorders, control-room 
boards, and dedicated transmitter. 

Then there's the antenna problem. 
In many instances, an additional tow- 
er will have to be put up for HDTV. 
And we shouldn't forget the problem 
of the required extra channel space, 
which just isn't available in all market 
areas. Direct-broadcast satellite will 
short circuit some of the above prob- 
lems, but only at the expense of the 
local broadcasters who would protest 
its adoption. 

Given all of the above, I suspect 
that the FCC will start seriously con- 
sidering authorizing the use of one of 
the "enhancing" systems that pro- 
vides a better and wide-screen pic- 
ture from the current NTSC system. 
For the broadcasters, the equipment 
required to encode additional infor- 
mation into their present transmis- 
sion systems should be relatively 
inexpensive as such things go. For 
the consumer, however, I suspect 
that the price of an enhanced TV sys- 
tem will move it out of the casual 
purchase category. 

Which brings me back to the same 
old question — is there a large enough 
audience for HDTV Cor enhanced TV) 
to make it a commercially viable en- 
terprise? The fact that you can get a 
much better picture from a videodisc 
than a video tape hasn't had much 
positive impact on videodisc sales. 
Obviously Japanese and U.S. man- 
ufacturers would like to sell ail sorts 
of newly developed enhanced-TV 
goodies to the American public. But 
even if he had the money, is John Q. 
really interested? R-E 



LICENSED 

ELECTRONIC TECHNICIAN! 




n at home in spare time. 
" No previous experience needed! 



No costly schooJ. No commuting to class. 
The Original Home-Study course prepares 
you for the "FCC Commercial Radio- 
telephone License."This valuable license is 
your professional "ticket" to thousands of 
exciting jobs in Communications, Radio- 
TV, Microwave, Maritime, Radar, Avionics 
and more... even start your own businessl 
You don't need a college degree to qualify, 
but you do need an FCC License. 
No Need to Quit Your Job or Go To School 
This proven course is easy, fast and low 
cost! GUARANTEED PASS— You get your 
FCC License or money refunded. Send for 
FREE facts now. MAIL COUPON TODAY! 

' GomflMND wibVucfioris" 

FCC LICENSE TRAINING, Dept, 90 
P.O. Box 2824, San Francisco, CA 94126 
Please rush FREE details Immediately! 

NAME . 



ADDRESS . 
CITY 



. STATE . 



.ZIP. 



1 1: \k\ vi ii 

CLEANING/MAINTENANCE/REPAIR 

EARN UP TO $1000 A WEEK, WORKING 
PART TIME FROM YOUR OWN HOME! 




THE MONEY MAKING OPPORTUNITY 
QFTHE199u*S 

IF you are able to work with common small hand 
tools, and are familiar with basic electronics (i.e. able 
to use voltmeter, understand DC electronics). . . . 
IF you possess average mechanical ability, and have a 
VCR on which to practice and leam. . . .then we can 
teach YOU VCR maintenance and repair! 
FACT: up to 90% of ALL VCR malfunctions are due to 
simple MECHANICAL or ELECTRO-MECHANICAL 
breakdowns! 

FACT: over 77 million VCRs in use today nationwide! 
Average VCR needs service or repair every 12 to 18 
months! 

Viejo's4D0 PAGE TRAINING MANUAL (over 500 pho- 
tos and illustrations) and AWARD-WINNING VIDEO 
TRAINING TAPE reveals the SECRETS of VCR mainte- 
nance and repair— "real world" information that is 
NOT available elsewhere! 

Also includes all the info you'll need regarding the 
BUSINESS-SIDE of running a successful service op- 
eration! FR£E | NF0RMATmN 

CALL TOLL-FREE 1-800-537-0589 
Or write to: Viejc Publications Inc. 

5329 Fountain Ave. 
Los Angeles, CA 90029 Dept. RF. 



m 

H 

rn 



to 



75 



CIRCLE 178 ON FREE INFORMATION CARD 



COMPUTER CONNECTIONS 



MS-DOS 5.0. 



JEFF HDLTZMAN 



D 



o 

O 

£ 
o 



OS 5.0 is finally here — and 
(it's a winner. DOS now in- 
cludes a frugal approach to 
memory usage as well as the most 
important must-have utilities. File util- 
ities face off squarely against prod- 
ucts including the Norton Utilities and 
PC Tools; built-in memory manage- 
ment facilities now compete favora- 
bly with products from Quarterdeck 
(QEMM) and Qualitas (386MAX). 
The third-party products are generally 
more powerful and more versatile 
than those provided by DOS. But for 
the majority of tasks performed by 
the majority of users, it may just be 
that DOS and its new utilities are 
good enough. 

New features 

The most important feature of 
DOS 5.0 is the ability to load part of 
itself into the High Memory Area 
(HMA). the first 64K of memory 
above the 1MB mark. (Normally 
memory above 1MB is unavailable to 
DOS programs, but due to a quirk in 
the Intel addressing scheme, real- 
mode DOS programs can get at the 
first 64K of extended memory with- 
out switching the microprocessor 
into protected mode. Although use of 
the HMA has been understood for 
several years, Digital Research's DR- 
DOS, released about a year ago, was 
the first and, until recently, the only 
operating-system product to use it. 
The HMA is only available on 286 and 
higher machines with extended mem- 
ory.) By loading DOS in the HMA. you 
can boot your machine with much 
more memory than before. For exam- 
ple, I now boot with about 625K of 
free memory. 

DOS 5.0 also includes a 386/486 
memory manager that can map RAM 
into upper memory blocks CUMB), 
unused address space in the area be- 
tween 640K and 1MB. You can then 
install device drivers and TSR's in that 
area. For example, I load device driv- 
ers for a disk cache and a RAM disk, 
a special video driver for a Hercules 
Graphics Station Card, several key- 



board-related TSR's, a mouse dnver, 
and LANtastic networking soft- 
wans — and still have about 625K of 
free conventional memory. That's a 
nice feeling. But does it work? 

It sure does. Microsoft wanted to 
avoid the kind of controversy that sur- 
rounded the release of DOS 4,0, so 
the company went through extensive 
qualification procedures (including 
some 7000 beta testers). And it 
shows, I've got a fairly complex set- 
up, including a SCSI-based hard disk, 
the 34010-based Hercules card, tape 
backup unit, and networking interface 
card. Installation was smooth and 
documentation clear; it all worked the 
first time, without a hitch. 

Goodies 

DOS 5,0 includes lots of neat little 
goodies, including built-in help mes- 
sages for most commands, that may 
take the wind out of utility vendors' 
sales. (Some of those utilities were in 
fact licensed from those vendors, 
who have already announced en- 
hanced versions.) Following are se- 



lected highlights of some of the 
updated commands. 

The Del command accepts /p to 
prompt you to confirm file deletion. 
The Devicehigh command loads de- 
vice drivers into UMB's. The Dir com- 
mand will sort files in forward or 
reverse order by name, extension, 
date/time, and size: you can also dis- 
play by attribute (hidden, system, 
read-only, archive); you can include 
subdirectories; there are other op- 
tions as well; and you can set up an 
environment variable (DIRCMD) that 
specifies your favorite format. 

Doskey provides a command-line 
editor/macro/history facility like CED 
and DOSEDIT. 

The Format command has a 
"quick" option (/q) that empties the 
file allocation table (FAT) and root di- 
rectory of a floppy disk, but does not 
erase the data area (or scan for bad 
sectors). 

The Graphics command, though 
slow, at long last supports all stan- 
dard video modes and numerous 
printers, including LaserJets. 



MS-DOS Shell 



File Options Uieu Inta Help 



C:M.ftNTAST[ 

SJfl [^)B lm*S L3D L3E IZ3F 
C3N EDO £n]? S9 E23R ES)S 



Directory Tree 



I-Cj DOS 
-£j E2WE 

SSEMU 
— £d bulletin 

■f£l LANTASTI .NET 

°~\ LOTUS 

LU MAG2 

■ r~l NORTON 

j-Pj 0LD_D0S.l 

Q PC INDEX 

Pn pcflus 
i pro 



SElfi EsDH QC LZJD CUE LZ1F 
i~°in cdo E3P [EflE S3R S3S 



Birectorij Tree 



00 ARCS 

D MT 

CD BKSHLF 

| CZPC 

■O C0MPTQNS 

-0j DISC PASS 

-ri dos 

-rj ee 

-00 FAX 

-P~| INFO 



lug esjh cri C3J 

E3T 



C2K cz)L r^i N 



C:\LflNTflSTIv**, 



E3 A1LANB10.EXE 

El CONFIG .SVS 

F3 IMS TALL .EXE 

m I MS TALI. .FLS 

13 INSTALL .HLP 

E3 I.ANCACHE.EXE 

H LANCKECK.EXE 

Eh LANCHECK.HLP 

B LANPUP .EXE 

F3 HET .EXE 

E NET .HLP 



CZ]G (H3H C31 CM 
EST 



AUTOEXEC. BAG 



E) AUTOEXEC. BAK 

E3 AUTOEXEC.BAT 

El AUTOEXEC. LAN 

fSh AUTOEXEC. MOW 

E A0AL0N .TXT 

ESJ BBftSH .BAK 

E BRASH .TXT 

H CUE .BAT 

E3 COMMAND .COM 

B CONFIG .BAC 



B,Z5B 


89-13-98|n 


13, 26? 


09-14-38 


123 


10- IB -98 


62,845 


85-29-98 


1,168 


BS-2S-3B 


8,174 


85-25-30 | 


■3,971 


BS-31-9B I 


13,181 


05-03-90 I 


4,937 


85-21-90 I 


S,509 


05-22-98 I 


12,853 


05-25-90 ■ 


46,872 


85-31-98 ffl 



FlB=flct jotis Sfcif t>F9=Cp«fiand Pyonpt 



C3K CZJL LZ1H 



154 B9-29-9B|n 



82-25-91 

8225-91 I 

1B-11-98 

11-05-98 

11-B8-90 

B4-3B-91 

84-38-91 

10-18-98 

B7-24-87 

B9-29-9B 1 4 



11:34a 



FIG. 1— MS-DOS 5.0 combines users' most- requested features in a comprehensive pack- 
age that frees 45K of conventional memory on 266 and 366 machines, has built-in 
undelete and unformat utilities, and a file manager/task swapper. This is the DOS you've 
been watting for. 



76 



RE Engineering Admart 



Rates: Ads are WyIW. One insertion $995 each. Six insertions $950 each. Twelve 
insertions $925 each. Closing date same as regular rate card. Send order with remittance to 
Engineering Admart, Radio-Electronics Magazine, 500-B Bi-County Blvd., Farmingdale, NY 
11735. Direct telephone inquiries to Arline Fishman, area code-1-516-293-3000, FAX 
1-516-293-3115. Only WO% Engineering ads are accepted for litis Admart. 



HIOI 



MIDI 
PROJECTS 




BP182 — MIDI interfacing enables any so 
equipped instruments, regardless of the 
manufacturer, to be easily connected to- 
gether and used as a system with easy com- 
puter control of these music systems. 
Combine a computer and some MIDI instru- 
ments and you can have what is virtually a 
programmable orchestra. To get your copy 
send $6.95 plus $1.25 for shipping in the 
U.S. to Electronic Technology Today 
Inc., P.O. Box 240, Massapequa Park, 
NY 11762-0240. 



LINEAR IC EQUIVALENTS 
& PIN CONNECTIONS 



Linear IC 

Equivalents 
and Pin 
Connections 




BP141 — Shows equivalents & pin con- 
nections of a popular user-oriented 
selection of European, American and 
Japanese liner IC.'s 320 pages, 8 x 10 
inches. $12.50 Plus $2.75 shipping. 
ELECTRONIC TECHNOLOGY TODAY 
INC., PO Box 240, Massapequa Park, 
New York 11762-0240. 



FCC LICENSE 
PREPARATION 



The FCC has revised and updated the 
commercial license exam. The NEW 
EXAM covers updated marine and 
aviation rules and regulations, 
transistor and digital circuitry. 
THE GENERAL RADIOTELEPHONE 
OPERATOR LICENSE - STUDY GUIDE 
contains vital information. VIDEO 
SEMINAR KITS ARE NOW AVAILABLE. 

WPT PUBLICATIONS 
979 Young Street, Suite E 
Woodburn, Oregon 97071 

Phone (503)981-5159 Depf. 50 






CIRCLE 184 ON FREE INFORMATION CARD 



Loadhi lets you load TSR's into the 
UMB area on 386 and higher CPU's. 
Mem displays information about the 
amount of free memory and loaded 
programs. 

The Mirror command backs up im- 
portant information about your hard 
disk. Mirror also optionally installs a 
TSR that keeps track of deleted files. 
Undelete and Unformat use that in- 
formation to help in case of disaster. 

Mode now lets you specify 43- and 
50-ltne VGA video modes, and key- 
board repeat and delay rates; it also 
supports COM3 and COM4 at rates 
as high as 19,200 bps. 

QBasie. which supersedes 
GWBASIC. is based on Microsoft's 
QuickBASIC environment. QBasie 
includes a hypertext help system but 
no printed documentation; programs 
can be saved in ASCII format to disk 
but cannot be compiled without the 
full QB environment. DOS 5.0 also 
includes a full-screen editor; the edi- 
tor is the QBasie environment. (For 
comparison, invoke EDIT.COM then 
QBASIC /EDITOR.) And yes. Edlin is 
still included. 

Ren (rename) still has not been up- 
graded; I guess I'll continue to use my 
800-byte 1985-vintage utility to re- 
name subdirectories. Nor is there a 
Move command, although you can 
use the DOS Shell to move files. 

Tree displays a graphical view of 
your directory structure, but is quite 
slow. I've got a 500- byte 1985-era PD 
utility that works ten times faster. 



Undelete and Unformat may cause 
trouble for the Norton Utilities. Sys 
will make a disk bootable whether it is 
empty or not. 

In addition to ANSI .SYS and DRIV- 
ER SYS, DOS 5.0 now includes de- 
vice drivers for setting up a RAM disk 
(RAMDRIVE.SYS) and a disk cache 
(SMARTDRVSYS); these drivers su- 
persede the ones included with Win- 
dows 3.0. 

Another device d river 
C386EMM.EXE) provides EMS mem- 
ory emulation on a 386 or higher 
CPU: it can also optionally map RAM 
into the UMB area. To avoid conflicts 
with various hardware adapters. 
386EMM. EXE includes options for in- 
cluding and excluding particular ad- 
dress ranges, and other options for 
specifying the address of the EMS 
page frame, and the number of task- 
switching handles and register sets. 

Installation is clean and easy; if 
you're upgrading from a previous ver- 
sion of DOS, the process saves your 
old DOS version in a separate sub- 
directory, and even forces you to 
create a bootable backup floppy in 
case something goes wrong. 

DOS is DOS, not Windows or 
OS/2 

DOS 5.0 includes a file manager 
called DOSSHELL that allows you to 
perform standard file manipulation 
(copy, move, rename, run, view), that 
can serve as a launching pad for your 
applications, and that can even 



switch among several DOS pro- 
grams. It does not however perform 
multitasking in the manner of DE- 
SQview or OmniView (to say nothing 
of Windows or OS/2). So you can't 
download files from your favorite 
BBS while simultaneously working in 
your word processor; you'd have to 
use Windows, OS/2, or a competing 
package for that. 

Conclusions 

Microsoft has really done its home- 
work on DOS 5.0. On one hand, it 
has users' most requested features: 
It returns a big 45K chunk of RAM to 
the user, obviates the need for more 
than half a dozen utilities (DOS shell, 
keyboard enhancer, 386 memory 
manager, disk cache, RAM disk, un- 
delete and unformat utilities), and al- 
lows large disk partitions (2 GB). You 
can get more powerful versions of 
these utilities from other vendors. 
But you may not need to — or want to. 
DOS 5.0 has some glaring deficien- 
cies, but most of the new additions 
are worthwhile. In short, it works. 
Bugs may turn up in the future, but 
DOS 5 has already shown itself more 
reliable, not to mention useful, than 
its predecessor. 

On the other hand, with the re- 
sources Microsoft has at its disposal, 
surely it could have included a DE- m 
SQviewtype of multitasker. Why not? % 
DOS 5.0 is careful not to infringe on jjj 
the multitasking turf staked out for =i 
Windows (and OS/2). 55 



m 

m 



77 



DIGITAL VIDEO STABILIZER 
ELIMINATES ALL VIDEO COPY 
PROTECTIONS 




While watching rente.) 
movies, you wilt notice an- 
noying periodic color 
darkening, color shift, ur> 
wanlod linns, Hashing or 
lagged edges. This is 

caused by the copy protec- 
tion jamming signals em- 
bedded In the video 'ape, 
such as Macrovislon copy 
protection. Digital Video 
Stabilizer: RXH compJelely 
ellmtnales all copy prelec- 
tions and }amming signals 
and brings you crystal clear 
pictures. 

FEATURES: 

• Easy to use and a snap 
to Install 

•Slaie-of-the-art in- 
tegrated circuit lechnol- 

• 1 56% automatic - no 

need for any 
troublesome adjust- 
mants 

• Compatible to all types 
ofVCRsandTVa 

#The best and most axctt- 
ing Video Stabilizer In 
the market 

• Ught weight (3 ounces) 
and Compact (1x3.5k5 ) 

• Beau! J u. deluxe gift box 

• Uses a standard 9 Volt 
battery which wilt last 1 - 
£yearv 



WARNING : 

SCO 

Electronics and 
RXII dealers do 
not encourage 
people to use 
the Digital 
Video Stabilizer 
to duplicate 
rental movies 
or copyrighted 
video tapes. 
RXII is in- 
tended to stabi- 
lize and restore 
crystal clear 
picture quality 
for private 
home use only. 

( Dealers Welcome ) 



ToOrder:SS9.95ea 

1-800-445-9285 

Visa, WC, COD M-F:9-6 

SCO ELECTRONICS INC, 

Dapt CRE9 S81 W. Merrick Rd. Valley Stream NY 11580 

Unconditional 30 days Money Back Guarantee 



S4 lor FAST UPS SHIPPING 

or 516-568-9850 

{baltery not included) 



CIRCLE 187 ON FREE INFORMATION CARD 





CABLETV 
DESGR AMBLER 

How You Can Save Money 
on Cable Rental Fees 








H 






o 


1 Unit 5+ 

JcrroldSBwrTri-BI. $99 $70 _„ .„ ..... ,„ 

SuptrTri-Bi (TBM }. 1 1 W....S75 US Cable will 

Jsrrold 450combo $189 ...$13o Beat Anyone's 

Scientific Atlanta $ 109....S75 p j Ji 

SA 8534™ $2S0....S19S ■ rrlce , 

Pioneer. $ 109...S79 Advertised In 

Oat KN 12 (w/VS) .$!<» ...$S5 (his Magazine ! 

Hamlin MLD 1200, m. $59 ^ 

Totem. „.._._ J169....S129 

Stirgate converter __ $89™I*9 
Panasonic TZPC145 $99 $19 

30 Days Money Back Guarantee 
Free 16 page Catalog 

Visa, M/C, COD or send money order to; 

US Cable TV Inc. De P t. kreq 

4100 N.Powerline Rd, Bldg F-4 
Pompano Beach, FL 33073 

1-800-772-6244 


o 

rr 

LU 

_l 
LU 

6 
Q 
< 

rr 


For Out Record 

[. the undersigned, do hereby declare under penalty of per- 
jury that all products purchased, now and in the future, will 
only be used on Cable TV systems wi th proper authorization 
from local officials or cable company officials in accordance 

with all applicable federal and state laws. FEDERAL AND 
VARIOUS STATE LAWS PROVIDE FOR SUBSTANTIAL 
CRIMINAL AND CIVIL PENALTIES FOR UNAUTHORIZED 
USE. 
Date: 

Signed r 


78 


No Florida Sates! 



The question now is: What next? 
There is talk that the next version of 
DOS will include built-in networking, 
an installable file system, multiple 
concurrent DOS sessions, clean ac- 
cess to extended memory... that sort 
of thing. 

Congratulations, Microsoft. When 
will we get a version of OS/2 that 
works as well? 

News bits 

IBM/Microsoft sparring con- 
tinues: IBM has been going to great 
lengths recently to demonstrate its 
independence from Microsoft. First, 
as reported last time, IBM has team- 
ed up with Micrografx to build a better 
graphics engine for OS/2. Since then 
the company has shown Digital Re- 
search's DR-DOS running under 
OS/2 2.0; both DR and IBM are com- 
mitted to full compatibility 

In addition. IBM has teamed up 
with Borland, whose C 4- + program- 
ming environment will be released for 
OS/2 2.0 by the end of the year. IBM 
is also developing its own 32-bit pro- 
gramming kit for OS/2. The company 
has publicly shown an early version of 
the OS/2 Presentation Manager 
(PM) that looks more like the Macin- 
tosh Finder than Windows; there are 
rumors circulating around that IBM is 
even looking into the possibility of 
licensing the Macintosh OS. Micro- 
soft, on the other hand, is busy at 
work developing a set of tools for 
porting OS/2 code to the Windows 
environment. 

Windows vs. OS/2 is becoming a 
religious issue in the trade press. Re- 
cent articles contain phrases like 
"pounded another stake through the 
heart of Presentation Manager," 
"Why OS/2 is dead." and so on. 
Sure, IBM doesn't want to become 
dependent on Microsoft. But both 
companies are developing products 
called OS/2, advanced versions of 
Windows and OS/2 have remarkably 
similar specifications, each company 
is licensed to the other's product, and 
both companies realize the devastat- 
ing effects of proprietary systems. 
We may end up with two different 
products — but there will be a high de- 
gree of compatibility between them. 

Multimedia mania. A high- 
ranking IBM official banged the drum 
for multimedia at Comdex once 
again, rattling off several challenges 
the industry must meet before main- 
stream multimedia becomes a reality, 



including standard data formats and 
API's (among IBM, Apple, Microsoft, 
and Commodore), a breakthrough in 
optical storage, reasonably priced 
full-motion video, compelling soft- 
ware, and extreme ease of use. 

On the equipment front, numerous 
companies are announcing expan- 
sion cards that provide digital audio 
capabilities for the PC: Covox (Sound 
Master) Brown-Waugh (Sound 
Blaster), Ad Lib Sound (Ad Lib), Me- 
diaVision (Pro Audio Spectrum), Tur- 
tle Beach Systems (MultiSound). 
These cards typically include MIDI 
compatibility, music synthesis, 44- 
kHz audio digitizing/playback, multi- 
source mixing. CD-ROM interface, 
microphone inputs, 12-bit A/D and 
D/A, audio amplifiers, etc. Prices 
range from $200 to $1000. 

Microsoft's multimedia strategy is 
about to blossom. In early summer, 
the company will release multimedia 
extensions to Windows. A multi- 
media version of Windows will be re- 
leased on CD-ROM, which will 
include all documentation in a hyper- 
text help facility, and will also include 
new accessory programs for access- 
ing multimedia data. The company is 
also scheduled to release a Multi- 
media Development Kit (MDK) dur- 
ing the summer. 

Friendly Windows develop- 
ment tools are sprouting up all over 
the place. Borland released a form- 
based package called ObjectVision 
several months ago, and more re- 
cently Turbo Pascal for Windows. Mi- 
crosoft returns to its roots with a 
release of BASIC called Visual 
BASIC. These products promise to 
revolutionize Windows product de- 
velopment efforts; watch for lots of 
powerful and fun new utilities and ap- 
plication programs. R-E 




"Clitttltvii, your fiuhi'y littx lwn rvpUnwt hy ti atrnptuer.' 



CIRCLE 188 ON FREE INFORMATION CARD 



NRI gives you two unbeatable 

opportunities for top pay, security, 

even a business of your own. 



Everybody wants to get ahead, but most 
people want assurance they're making the 
right job choice. According to the US. 
Department of Labor, jobs for electricians 
and air conditioning, heating and refrigera- 
tion technicians offer high earnings and 
good job prospects. Now MR] can show you 
how to go after the high earnings, the steady 
pay increases, even how to be your own 
boss in a business of your own. You'll get 
all the skills to get there. No night school, 
no need to quit your job until you're ready 
to make your move. NRI trains you right at 
home in your spare time. 

No Experience Needed. 

NRi starts you with the basics, then builds 
your knowledge and skill a step at a time, 
all the while adding practical know-how 
through hands-on training. You even get 
tools you need on the job or in a business 
of your own. Over a million and a half stu- 
dents have trained the NRI way since 1914. 

Be an Electrician. 

Each year, the demand for skilled 
construction, maintenance, commercial 
and utility electricians continues to grow. 
The U.S. Department of Labor estimates 
that close to 100,000 new jobs will open up 
in the next ten years -a conservative 
estimate compared to industry and union 
predictions. 

And few jobs can match the money-making 
potential of the qualified electrician. You 
can earn a salary in excess of $25,000 or 
be your own boss with your own electrical 
contracting business. 

Only NRI gives you this kind of practi- 
cal, job-oriented, hands-on training. 

You master practical skills like this with the 
equipment, test instruments, and training 
materials included in your course . . . you 
duplicate on-the-job wiring with your NRI 
Residential Wiling Practical Lab®. . . you 
learn professional troubleshooting using 
your Voit-Ohmmeter and Clamp-On 
Ammeter to test the circuits you build up 
on your NRI Circuit Demonstrator . . . and 
by installing and testing an electronic- 
programmable thermostat and a micro- 
processor-controlled remote power 
control, you come to understand today's 
electronics as it applies to the latest 
devices electricians install and repair. 
Training in the latest need-to-know 
electronics required of today's 
electrician. 

NRI created this new course so you can 
move from the simplest fundamentals of 
electricity, through professional wiring and 
trouble-shooting techniques, all the way up 
to mastering the practical field skills you 
need to become today's electronic-smart 
electrician. Be an electrician, it could be 
the best and last job choice you'll ever have 
to make. 




Be an Air Conditioning, 

Refrigeration, Heating 

Technician. 

When it comes to targeting the good 
paying jobs, regular pay increases, and 



the steady demand for your skills in this 
field, the U.S. Department of Labor scores 
a solid hit.. -high earnings and good job 
prospects attract many individuals... 
because people in business depend on 
their air conditioning, heating, and refrig- 
eration systems, the need for ski I led tech- 
nicians to do maintenance work has to be 
met regardless of swings in the economy. 
Add millions of window units in older 
homes requiring maintenance and repair; 
heat pumps so popular they're now as 
common as furnaces; commercial 
refrigeration alone calling for skilled tech- 
nicians to install and service walk-in cool- 
ers, freezers, ice makers, and food cases. 

Wherever you look, there's tremendous 
opportunities for the trained air 
conditioning, refrigeration, and heating 
technician. 

NRI training so complete, 
professional tools even included. 

NRI trains you lor this lucrative field, gets 
you ready to land a good paying job, pick 
up extra income in your spare time, even 
start a business of your own. You're ready 
to jump right in because NRI includes the 
tools you need: system analyzer, leak 
detector, tubbing and joint tools, a top- 
quality vacuum pump for purging systems, 
plus demonstration panel units for hands- 
on systems training. Graduates of our 
Master Course also get optional free 
residential training at the world-famous 
York Institute in York, PA. 

Go a f ter h igh earn i n gs , pay i ncreases , 
a business of your own. 

Send for NRI's free catalog. Find out what 
hands-on projects you do, the profes- 
sional tools you train with, and the future 
that can be yours. Act today. 



SEND COUPON TODAY FOR FREE NRI CATALOG' 



nor* „ '-^to,. 



MW^WM SCHOOLS 

McGraw-Hill Conlinuing Education Center 

4401 Connectieul Avenue. NW. Washington. DC 20008 



tk'if! tf 

ilnii , E , 



For Career courses 

approver) under CI Dill 

□ cnecit lor details 



CHECK ONE FREE CATALOG 
D Electrician 
G Air Conditioning Heating 

& Refrigeration 
□ Microcomputer Servicing 
D Small Engine Repair 
D Appliance Servicing 
D Lncksmithing 



ONLY 

C Automotive Servicing 

□ Bookkeeping & Accounting 
n Photography 

O TWAudioA/ideo Servicing 

□ Telecommunications 
3 Desktop Publishing 
G Building Construction 





a Data Communications 
G Industrial Electronics 
□ Computer Programming 
C Electronic Design Technofogy 
c Cellular Telephone 
G Digital Electronic Servicing 
G Basic Electronics 



-Age. 



Street. 



Ci1y/Slale/Zip_ 



Accredited Member National HomeSludy Council 



4218091 I 



m 

a 

m 
S 
00 
m 
33 

— I 

<£> 

to 

— L 

81 



ELECTROMAGNETIC THEORY 



continued from page 59 



CO 

9 

z 
o 

CE 
H 
O 

UJ 



o 

Q 
< 

a: 



that are bound directly to the 
atom and cannot flow. If N is of 
magnitude 1 and is normal to the 
surface then 

o- b = P-N(C/ni2). 
Imagine a Gaussian surface in- 
side the dielectric. With a 
nonuniform charge distribution 
some of the bound charges will be 
displaced across the surface by P. 
leaving a net charge within the 
surface. In the same manner that 
we found V-E = pe , where p is the 
volume charge density of all the 
charges contributing to E, we 
can see that the volume charge 
density in the dielectric is 

V.p=- Pb (C/m 3 ). 
The negative sign means that the 
dipole moment per unit volume, 
P, points from negative to 
positive in the dipotes. 

It is customary and convenient 
to consider a field associated with 
just the free charge density p, 
since p b is due to the response of 
the material. That field must be 
due to the total charge density 
less the bound charge density, 
therefore 

Pf=p-pb = V-t E + V-P = VKE+P]. 
The term in brackets is called the 
displacement field vector 
D = e E + P(C/m2). 

In simple dielectrics, P and E 
are parallel, and the following re- 
lation holds true 

D = e (1 + K ) E = eE- 
e D can now be interpreted as the 
ability of empty space to support 
an electric field, and is called the 
permittivity of free space, e is the 
permittivity of the material. A 
commonly used quantity is the 
dielectric constant 

K = 1+x = e/t . 
K is greater than 1 for any materi- 
al, and goes to infinity for a con- 
ductor because E = in a 
conductor. K can be thought of as 
a measure of the modification of 
free space by the presence of a 
material. 

From our previous analysis, we 
have obtained one of Maxwell 
equations. Gauss' law which 
reads 

vD = Pl . 
Gauss' law says that the apparent 
spreading out of the displace- 
ment field vector D through a 
Gaussian surface is due to the 
density of free charges inside. 
Gauss' law doesn't say, however, 



that D is not producing a swirl. 
The static E contribution can't 
produce swirling, but the P con- 
tribution can. 

Capacitance 

We know that two conductors, 
separated by a dielectric with di- 
electric constant k, form a capac- 
itor. If one conductor has charge 
+ q and the other - q, the mea- 
sure of the amount of charge that 
must be placed on a conductor to 
change its potential by one volt is 
called the capacitance, which is 
in units of coulombs per volt 
C = q/V (farads). 

If the free charge q increases, 
the displacement field vector D, 
which equals the e k field also 
increases. That causes a propor- 
tionate increase in voltage as E 
rises. Given a particular charge 
q, the only way to change the ca- 
pacitance is to change the volt- 
age. That can be done by 
changing the charge separation 
distances or by changing the 
properties of space to give dif- 
ferent E's. Simply filling the sepa- 
ration space with a material of 
greater dielectric constant re- 
duces the E field in that space, 
which reduces the voltage and in- 
creases the capacitance. 

We can use Gauss' law, without 
involved calculations, to deter- 
mine the change in the electric 
field when any capacitor is filled 
with a dielectric. In empty space, 
P = O and all the charges are free 
charges, therefore 

V.D/eo = V-E = P( /e , 

and 

YD/e = YxE = O. 
If the space is filled with a simple 
dielectric, D = e kE, therefore 
V-D/e = V-ftE= p|/«o. 

P is aligned with E so there is no 
apparent rotation and 

VxD/e = Vx/fE = O. 

The divergence and curl of E 
completely characterize the field. 
By comparison, the E for a 
charged capacitor with empty 
space as a dielectric is the same 
as kE for the same charged ca- 
pacitor with a dielectric constant 
k. In a capacitor filled with a di- 
electric, E is reduced by Ilk. The 
capacitance C = q/V is increased 
by k since the voltage potential V 
is reduced by 1/Jf. 

In our next edition, we'll look at 
the effects of electric charges in 
motion. We'll see that another 
type of field, the B field, is re- 
quired to describe the magnetic 
forces associated with them. R-E 



EQUIPMENT REPORT 



continued from page 18 



frequency steps. 

A number of scanning functions 
are available: full memory scan, mem- 
ory block scan, and seek scan, (with 
two delay modes). The R8 can also 
be set to scan from the frequency of 
VFO A to VFO B. The two VFO's are 
available so that you can instantly 
switch and tune between two dif- 
ferent frequencies. The second VFO 
can be thought of as a sort of tempo- 
rary memory location. One of the nic- 
est features is that you can instantly 
transfer the frequency of the active 
VFO into the inactive one. So if 
you're tuning and come across an 
interesting signal — but not the one 
you're looking for — you can put it in- 
stantly in the inactive VFO as you 
continue your search. Returning to 
the interesting frequency is only two 
keystrokes away. 

A partial list of its built-in features 
include an RS-232-compatible inter- 
face that allows your computer to 
take complete control over all func- 
tions of the receiver. Two antenna 
connectors are provided. One is a 
coaxial SO-239 connector for 50- 
ohm antennas, the second is a 
spring-clip connector that can be 
used for 50- or 500-ohm antennas. 
The appropriate antenna can be se- 
lected from the front panel. An exter- 
nal-speaker jack and a headphone 
jack are provided, as are line-level au- 
dio connectors Cfor recorders or 
CW/RTTY demodulators! A mute 
connector lets the R8 be used in con- 
junction with a transmitter. 

We were impressed by the quality 
of the Drake R8. It is easy to use 
thanks in part to the clean layout of 
the controls, and to Drake's decision 
not to clutter up the front panel with a 
lot of unnecessary controls (which 
some manufacturers seem to think 
looks "hi tech"). We were even more 
impressed by the control the R8 gave 
us to hear the weaker signals we 
would have simply ignored on other 
world-band radios. 

If you're not familiar with world- 
band radio, don't even think of the 
R8. You simply won't appreciate what 
it can do for you. But if you're a short- 
wave enthusiast who is looking for 
something special and have about 
$1000 to invest, then we've found the 
receiver of your dreams. R-E 



82 



MARKET CENTER 



FOR SALE 



TURFS: "oktest." "latest.' Parts and schematics. 
SASE tor lists. STEINMETZ, 751 9 Maplewood Ave., 
RE, Hammond, IN 46324. 



HAVING trouble with IC's? We specialize in locating 
"hard to find" items! Low prices on eproms. micros, 
pals. Custom programmers built to your specs. 
CHAFFIN ELECTRONICS, (8I4) 974-4456 9AM to 
5PM EST. 



CLASSIFIED AD ORDER FORM 

To run your own classified ad, put one word on each o( the lines below and send this (orm along with your check to: 

Radio-Electronics Classified Ads, 500-B Bi-County Boulevard, Farmingdale. NY 11735 

PLEASE INDICATE in which category of classified advertising you wish your ad to appear. For 

special headings, there is a surcharge of $25.00. 

( ) Plans/Kits ( ) Business Opportunities ( ) For Sale 

j | Education/ Instruction ( ) Wanted ( ) Satellite Television 

Special Category: $25.00 

PLEASE PRINT EACH WORD SEPARATELY, IN BLOCK LETTERS. 
(No refunds or credits for typesetting errors can be made unless you clearly print or type your 
copy.) Rates indicated are for standard style classified ads only. See below for additional 
charges for special ads. Minimum: 15 words. 



1 


6 


11 


16 ($49.60) 


21 ($65.10) 


26 ($80,60) 



2 


7 


12 


17 ($52.70) 


22 ($68.20) 


27 ($83.70) 



3 


8 


13 


18 ($55.80) 


23 ($71 .30) 


28 ($86.80) 



14 



19 ($58.90) 



24 ($74.40) 



29 ($89.90) 



5 


10 


15 ($46.50) 


20 ($62.00) 


25 ($77.50) 


30 ($93,00) 



31 ($96.10) 32 ($99-20) 33 ($102.30) 34 ($105.40) 35 ($108.50) 

We accept MasterCard and Visa for payment of orders. If you wish to use your credit card to pay for your ad fill 
in the following additional information (Sorry, no telephone orders can be accepted.): 



Card Number 



Expiration Date 



Please Print Name 



Signature 



IF YOU USE A BOX NUMBER YOU MUST INCLUDE YOUR PERMANENT ADDRESS AND PHONE 
NUMBER FOR OUR FILES. ADS SUBMITTED WITHOUT THIS INFORMATION WILL NOT BE ACCEPTED. 
CLASSIFIED COMMERCIAL RATE: (for firms Or individuals offering commercial products or services) 
$3.10 per word prepaid (no charge for zip code)... MINI MUM 15 WORDS. 5% discount for same ad in 6 
issues; 10% discount for same ad in 12 issues within one year; if prepaid. NON-COMMERCIAL RATE: (for 
individuals who want to buy or sell a personal item) $2.50 per word, prepaid....no minimum. ONLY FIRST 
WORD AND NAME set in bold caps at no extra charge. Additional bold face (not available as all caps) SSe 
per word additional. Entire ad in boldface. $3 70 perword. TINT SCREEN BEHIND ENTIRE AD: 53.85 per 
word. TINT SCREEN BEHIND ENTIRE AD PLUS ALL BOLD FACE AD: S4.50 per word. EXPANDED 
TYPE AD: $4.70 per word prepaid. Entire ad in boldface, S5.60 perword TINT SCREEN BEHIND ENTIRE 
EXPANDED TYPE AD: $5.90 per word. TINT SCREEN BEHIND ENTIRE EXPANDED TYPE AD PLUS 
ALL BOLD FACE AD: $6.60 per word. DISPLAY ADS: 1" x 2W— $410.00; 2" x 2W'— $820.00; 3" x 
2W — $1230.00. General Information: Frequency rates and prepayment discounts are available. ALL 
COPY SUBJECT TO PUBLISHERS APPHOVAL. ADVERTISEMENTS USING P.O. BOX ADDRESS WILL 
NOT BE ACCEPTED UNTIL ADVERTISER SUPPLIES PUBLISHER WITH PERMANENT ADDRESS 
AND PHONE NUMBER. Copy to be in our hands on the 5lh of the third month preceding the dale of the 
issue, (i.e.. Aug. issue copy must be received by May 5th). When normal closing date falls on Saturday, 
Sunday or Holiday, issue closes on preceding working day. Send for the classified brochure. Circle Number 
49 on the Free Information Card. 



COMPUTERS AT/XT compatible systems and 
components at discount prices Catalog $2.00. re- 
fundwith first order. MPS ENTERPRISES, Box 
1048, Lemon Grove. CA 91940. 

ENGINEERING software, PC/MSD0S. Circuit 
design and drawing, PCB layout, Logic sim- 
ulation, FFT analysis, Mathematics, Circuit 
analysis. Call or write for free catalog. 1 
(800) 728-3805, BS0TT SOFTWARE, INC., 
444 Coiton Rd., Columbus, OH 43207. 



Quality Microwave TV Antennas 



B WIRELESS CABLE - IF IS - MMDS - Amateur TV 
Uim High Gam 50* (+1 ■ Tuneaole 1.9 to J.T Gin. 
• 36-Channel System Complete 5149.95 
• i:-ClBnnel System Complete SI 14.95 
• Cil « write (SASE1 for "FREE" Calaloo. 
PHILLIPS-TECH ELECTRONICS 
P.O. Bui 8533 . Scottsdale. A7 85252 
: (602) 947-7700 IS3.00 Crcdil ill ptiuii orfiri] 
WARRANTY MaiterCard ■ Visa ■ COD'S ■ Quurtfty Prtclnf 



RESTRICTED technical information: Electronic sur- 
veillance, schematics, tocksmithing, covert sci- 
ences, hacking, etc. Huge selection. Free 
brochures. MENTOR-Z, Drawer 1549, Asbury 

Park, N J 07712. 

CABLE TV converters: Jerrold, Oak. Scientilic At- 
lantic. Zenith & many others. "New MTS" stereo 
add-on: mute & volume. Ideal for 400 and 450 
owners! 1 (800) 826-7623, Amex, Visa, M/C accept- 
ed. B & B INC., 4030 Beau-D-Rue Drive, Eagan, 
MN 55122. 



CALL DOCTOR 

DESCRAMBLER 



...for symptoms 
relating to scrambled 
cable T.V. signals. We 
have » JERROLD 

• TOCOM • ZENITH 
•HAMLIN 'OAK 

• SCIENTIFIC 
ATLANTA. 

Six month 
warranty! We 
snip C.O.D. 
Lowest retail/ 
wholesale prices. FREE 
CATALOG: VISA, M.C., 
AM.EX. 

Global Cable Network 
1033 Irving St. Suite 
109 S.F..CA 94122 
NO CALIFORNIA 
SALES!!! 
OPEN SATURDAYS 





m 






1-800-327-8544 



83 



mmm 




CHOOSE FROM THE FOLLOWING PACKAGES: 



PKG.1... 



10 



PANASONIC 
1453G CONVERTERS 



S65 



PKG. '2... 

8 SCIENTIFIC ATLANTA $17C 
8536+ COMBINATIONS* If J 



PKG. '3... 

5 SCIENTIFIC ATLANTA $91E" 
8580 COMBINATIONS T fc 111 



PKG. 4... 



Ah MIX AND MATCH 



ADD-ONS 



$45" 



ALL EQUIPMENT IS BRAND NEW, FACTORY FRESH !!! 

(800)234-1006 CAK||EADV 



WANTED; old, Western Electric, Mcintosh, Altec, 
Marantz, Jensen, JBL, EMT, Electrovoice. RCA, 
Telefunken. Westrex, Fairchild, Fisher, Dynaco; 
tubes, speakers, amplifiers, (713) 728-4343, MA- 
URY CORB, 12325 Ash croft, Houston, TX 77035. 

TUBES, new, up to 90% off, SASE, KtRBY, 298 
West Carmel Drive, Carmel, !N 46032. 



WIRELESS CABLE RECEIVERS 1.9 TO 2.7 GHz 



30 CH PARAeOLIC DISH SYSTEM S173.90 
30 CH ROD ANTENNA SYSTEM S!93 30 

30 CH CrfYSTAl CONTROl LED SVSTEM S»4 -9S 
SUN MICROWAVE IHT'L. INC. SEND SI. 18 FOR 
P II f :■!. .1 ■■ v :■ CATALOG OK THESE 

PHOENIX. AZ 5505? '■«:: OTHER FINE 

602 I3D-1M5 VIDEO PRODUCTS 

OOANIIT* DISCOUNT! 



Q 



ORDERS 0HLT 1-BW- W-4190 CODE 9/S3 



RADIO software, PC/MSDOS 5.25" 360k disk. 23 
programs including subprograms. INTER MOD — 
RFRANGE — SWRCALC — dBCALC — PA- 
TH LOSS — more! Great for technicians and stu- 
dents. Complete package $19.95. SPARTAN 
RADIO, PO Box 15178, Dept. RE, Spartanburg, SC 
29302. 

TB-3/SB-3 descrambler schematics with service in- 
formation. $30.00 each. Both for $50.00. S.A.S.E. 

for samples. JEC TECH, Box 94B, Pickerington. 
OH 43147. 

t.C.'S, capacitors, connectors, etc. DYNASTY 
ELECTRONICS, 200 South Semoran Blvd., Orlan- 
do, FL 32807. Fax (407) 381-0785. 

H-P 331 A distortion analyzer $245,00; Boonton 
230A power amplifier 10-500MHZ $125.00; H-P 
202H AM/FM signal generator 54-216MHZ $350.00; 
GR 1001 A AM generator 5kHz-50 MHz $235.00; 
TEK 575 curve tracer $375.00; H-P 7402A strip 
chart recorder as is $225.00. Older tube type equip- 
ment bargain prices. Catalog $5.00. EDI, 180 
Rodeo Drive, Brentwood, NY 11717. (516) 
242-6400. 



PERFECT CABLE CONNECTION !! 



Perfect Cable Connection IS tclally commitled 
to customer saiisfaciiorv Our primary concern 
is to provide you wilh the highest quality 
conveners and descramblers at trie lowest cost 
We employ lull time technicians to insure hassle 
Iree service and EroubTesnoot any situation. Call 
us today and let tis prove lo you why we are 
Irie Perfect Cable Connexion. 



■ 6 monlhs 100% pens i labor 
» 24 monlhs warranly available 

■ Foil technical support 

' On-line computer sysleiti 

- 30 days money back guarantee 

• Most orders shipped within 24 hours 

• Visa, M'C. AMEX - 5"!i 
, Dealers welcome 

■ COD. 




CO 
O 



WE WILL MEET OR BEAT ANY ADVERTISED PRICE 
IN THIS MAGAZINE. 



PERFECT CABLE CONNECTION 

702-358-2763 

2209 Oddie Blvd., Suite 321 

Spark, NV 89431 



Try the 

Bectnmics* 

bulletin board 
system 

(RE-BBS) 
516-293-2283 



The more you use it the 
more useful it becomes. 

We support 300 and 1200 
baud operation. 

Parameters: 8N1 (8 data 
bits, no parity, 1 stop bit) 
or 7E1 (7 data bits, even 
parity, 1 stop bit). 

Add yourself to our user 
tiles lo increase your 
access. 

Communicate with other 
n-E readers. 

Leave your comments on 
R-E with the SYS0P. 



RE-BBS 
516-293-2283 



JEHISBEIE 



FAMOUS "FIRESTIK" BRAND CB ANTENNAS 

AND ACCESSORIES. QUALITY PRODUCTS 

FOR THE SERIOUS CB'er. SINCE 1962 



FIRESTIK ANTENNA COMPANY 

2614 EAST ADAMS 

PHOENIX, ARIZONA 85034 



TEKTRONIX pie-owned oscilloscopes. 500-MHz 
model-7904 $3,200.00. 100MHz model-7603 
$1,200.00, with plug-ins, JOHN, 8500 Hilo Lane. 
Cottage Grove, MN 55016. (612) 459-5862. 

FM stereo transmitters. 88-108 Mhz, assembled, 
crystal controlled, internal audio mixers. Broadcast 
quality $100.00 — $200.00. Catalog: OREGON 
COMSYSTEMS, 1257 Siskiyou, Suite 132, Ash- 
land, OR 97520. 



■M:1=M.».I.1WI3=E« 

We specialize in a wide variety of technical 
information, parts and services for CB radios. 
10-Meter and FM conversion kits, repair books, 
plans, high-performance accessories. Thousands 
of satisfied customers since 1976! Catalog $2. 



CBC INTERNATIONAL 

P.O. BOX 31500RE, PHOENIX, AZ 85046 



BRAND new Tektronix 2247A 4-channel os- 
cilloscope. Never been out of box w/Quickpak. Will 
sacrifice (402) 438-3318. 

PHOTOCOPIER theory and repair manual. Secrets 
revealed. $19.95 LOTUS PUBLISHING, Dept. S, 
Box 1689, Guelph, Ont. N1H 6Z9. 

CABLE TV converters and descramblers. 
We sell only the best. Low prices. SB-3 
$79.00. We ship C.U.O. Free catalog. ACE 
PRODUCTS, PO Box 582, Dept. E, Saco, ME 
04072. 1 (800) 234-0726, 

CABLE descramblers (Jerrold) from $40.00. Tocom 
VIP test chip. Fully activates unit. Also Zenith test 
board. Fully activates Z-Tacs. $50.00. Call (213) 
867-0081. 



ANTIQUE RADIO CLASSIFIED 
Free Sample! ^^^f^&i 

Antique Radio's i^^OqjQjp 

Largest Circulation Monthly, [B@W o I 
Articles, Ads & Classifieds. ■ ^lv*«B | j 

6-Month Trial: $15, 1-Yr: $27 (S40-1st Class). 
A.R.C., P.O. Box 802-L9, Carlisle, MA 01741 



TV. notch filters, phone recording equipment, bro- 
chure $1 .00 MICRO THinc. Box 63/6025, Margate, 
FL 33063. (305) 752-9202. 

PHOTOFACT lolders under #1400 $5.00. Others 
$7.00. Postpaid. LOEB, 414 Chestnut Lane, East 
Meadow, NY 11554. (516) 481-4380. 

CABLE CONVERTERS all major brands info + 
orders 1 (800) 782-0552 FREEWAY INC. s.m.p.. 
PO 5036, Burnsville, MN 55337. 



PAV TU AMD SATELLITE 0ESCRAMBLING 
ALL NEW 1991 EDITION 



Our best yet The very latest in descrjm'biinfl circuits, bypasses, lutn-ofls- (or 
dote, wireirss gn-d satellite. Only $1 A .95-. Otter cay TV edirJpns-. Vol. i (Basics 
Ol All Svstemsj $14.95. 1909 Edition $14.95. Build satellite systems under S60D 
$1 2.95. Wireless Cable Handbodn s& 95. Any 1-W9 95 or 5#44,95. SciamblinQ 
News Monthly has all into f n the new "Plain Vamfla" dpscf-amWEfs which Em- 
ulate B'Wias VCii. Plus and Qriarv. $I9.95/Yr All new catalog £1 



Scrambling News. 155! Hertel Aue.. 
Buflalo. NY. 14216. COD'S ARE OK. (716) 874-2089 



SUPER low prices on computers, motherboards, 
hard and floppy drives, add-on cards. We have ev- 
erything. Full line of test equipment at unbeatable 
prices. Call for free catalog. APPLIED ELEC- 
TRONIC RESEARCH, INC., 4701 SW 45th Street. 
Ft. Lauderdale, FL 33314. (305) 987-9785. 



84 



/ ELECTECH / 

CABLE T.V. DESCRAMBLERS 

• All quality brand names • 
• All fully guaranteed • All the time ■ 
Knowledgeable Sales Sen/ice Department 
FOR FREE CATALOG 800-253-0099 



CIRCUIT Center — Complete circuit fabrication 
from single piece single sided to production multi- 
layer. Also — Laminate $5,50/sq. ft., etch $3.50/qt. 
Thru hole plating available too. CIRCUIT CENTER, 
Dept. 001, PO Box 128, Addison, IL 60101. (708) 
543-0671. 

PREVENT descrambler detection! Order Tech- 
Block today! Simple in-line connection. Only $19.95 
P.P.D. THE STAGE DOOR VIDEO, PO Box 518, 
Belleview, FL 32620. ForC.O.D.*s1 (800)395-4557. 

INTERFERENCE fillers, all channels. Best quality, 
cylinder type. Low prices. Visa, MC, COD accepted. 
1 (800) 872-5912. 

EXOTIC miniature electronic devices, catalog 
$5.00. refundable. F&P ENTERPRISES, Box 
51272, Palo Alto. CA 94303-L 

AC motor speed control — UL listed, 15A. 
1 20/220vac, dual independent inputs tor stall speed 
limit and thermistor probe included. Range 80°F 
minimum speed, 140°F maximum speed. $29.95 
plus $4.00 S&H. CONTROL OPTIONS, INC., 3298 
S. Acoma, Englewood, CO 80110. (303) 761-5927. 

SENCORE SC-61 waveform analyzer just factory 
updated $1500.00. BLS, PO Box 230014, Tampa, 
FL 33682. 

TECHNICIANS, hobbyists. New affordable pro- 
grammable power supply. For brochure contact: 
AMERICAN DIGITAL SYSTEMS, INC., PO Box 
22953. Denver, CO 80222. Tel Fax 1 (800) 424- 
ADSI. 



7 



v \ 

f roc 



-K * * * PRESENTING it - 

CABLE TV 
DESCRAMBLERS 

***** STARRING ***** 

JERROLD, HAMUN, OAK 

AND OTHER FAMOUS MANUFACTURERS 

• FINEST WARRANTY PROGRAM AVAILABLE 

• I CM/FIT RFTAII /WHOLESALE PRICES IN US 

• ORDERS SHIPPED FROM STOCK WITHIN 24 HIS 

• ALL MAJOR CREDIT CARDS ACCEPTED 
FOR FREE CATALOG ONLY 1 SOO-34 5-892 J 

FOR ALL INFORM ATJON 1-8 1 B~709-993 Tj 



PACIFIC CABLE CO., INC. 

7325' a Reseda Blvd.. Dept. 2106 

Reseda, CA 91335 



CABLE TV descr am biers converters, wholesale to 
all,weshipC.O.D.,examplesOak RTC-56 $125.00, 
M-35-B $35.00, X-12 $29.00, FTB-3 $69.00, 
Tocoms, Zenith, Jerrold, Hamlin, SA, etc. S.A.C., 1 
(BOO) 622-3799. 

RAW cable equipment, as is, Z-tac $35.00. RTC-56 
$45.00. M-35-B $18.00, Tocom $65.00, Texcan 
4040 $25.00, 400 QIC S25.00, same day shipping. 
(702) 647-3799. 

ELECTRONIC supermarket great buys! Surplus 
prices! Railroaders, builders, engineers, experi- 
menters, LSASE, FERTIK'S, 5400 Ella, Phila- 
delphia, PA 19120. 

TOCOM-Jerrold Impulse-Scientific Atlanta 8580 
& 8590 converters with two yr. warranties, also test 
modules for Star Comm 6 & 7s, all Tocoms, and 
Scientilic Atlanta. Full details. (219) 935-4128. 

DESCRAMBLERS cable TV converters, lowest 
prices, guaranteed, best quality, special Sacramen- 
to units. CNC CONCEPTS, INC, Box 34503, Min- 
neapolis, MN 55434. 1 (800) 535-1843. 



CBTV converters: Jerrold JSX DIC $19.00 DRX 
replacement (4040) $39.00, M35B $19.00, RKDM 
S55.O0, other brands in stock, minimum 10 lots 1 
(800) 395-2225. 

TOCOM and Zenith "test" chips. Fully activates 
unit. $50.00. Cable descramblers from $40.00. 
Orders 1 (800) 452-7090. Information (213) 
B67-0081. 



REMOVE 

LEAD 

VOCALS 

. From R»eortis& CD's 



Quid 9, 14 kit for uridw &G0 Mil*** 

mum* lead vocaje from slandanj 

stereo records. CD's, tapec or FW 

Lxoadceala. Easily conned* to any 

horn* component atweo. Perform 

live wift m* background*. You can 

be lia load singer at your Favorite 

band. Battled Plana. (4.95 

Weeds r Technologies 

14773 Llndwy Rd 

Ml Orab, Ohio 45154 . 



PLANS AND KITS 

DAZER personal protectors! Lasers! AM/FM/ln- 
frared transmitters! Detectors! More! Kits/as- 
sembled. Catalog $2.00. QUANTUM RESEARCH, 
16645-113 Avenue, Edmonton. Alberta T5M 2X2. 

SURVEILLANCE — Audio/video/infra-red/laser 
equipment. Industrial or private. 500 item catalog 
$7.00. SECURITY SYSTEMS, 3017G Hudson PL, 
New Orleans, LA 70131. 



REMOTE CONTROL REYCHAIN 



Complete w'm1nl-4fBnBmiUe' i: :: : 
fltid +5 vrfc RF. receiver:;:; 
Fully assembled including plans 
to build your own auto alarm;;; 

Qua niHy. d isco unts sya il a ble 

<!"■>/•. r\c Cheek,vja» ortnVC 

5>«i4.yO :- AcW S 3 shipping : 

Sox 14156, Fremont, C« 94539 

Fax (415) 531^-8442 




VISITECTINC, 
(41 5)531 -3425 



4 MITSUBISHI 
r» ELECTRIC 



►HER 

S/WtS 

flcqmmc 

arist.: 






SONY 



Welle 



HGaR 



roblemotic 



SIIRIICI 

( B A It £ m 



EPC PIONEER 



MCM Electronics 

We Can't Help Mentioning 
A Few Names 

Although name-dropping is usually frowned upon, 
we'll risk it so you'll know the kind of company we 
keep... and that you can get almost any part you could 
ever want from our huge MCM Catalog. Choose from 
more than 17,000 items, most of them in stock and 
ready to ship within 24 hours! 
Talk to friendly, knowledgeable | 
sales reps, get technical help 
when you need it and enjoy 
convenient, TOLL-FREE order- 
ing. All GREAT reasons why you | 
should be keeping company 
with MCM too! 

Call TOLL-FREE, 
1-800-543-4330, 

NOW to get your FREE 
SUBSCRIPTION to the 
MCM Electronics Catalog 



t£fi 


l 


^%a^H 


lMCM 

electronics 

a SPRING -1991 


^- 


4 



%c^ 



MCM ELECTRONICS 

B50 CONGRESS PARK DR. 
CENTERVILLE, OH 45459-4072 
A PREMIER Company 



DURACELL 

CRAMOUN 




RocKet 




FLUKE 

■aaaaaaaaaaaaaaaaaB 

CIRCLE 87 ON FREE INFORMATION CARD 



CO 

m 

13 



co 
m 
3D 

ID 

to 



85 



Cable Descramblers 



New Auto Tri-Bi guaranteed no flashing $165.00 

SB-3 399.00 ZENITH SUPER 

TRIMODE $109.00 SAAVI 1199.00 

SIAMLtN S99.00 TOCOM S319.00 

SCIENTIFIC- EAGLE $119.00 

ATLANTA S119.00 COPV GUARD $59.95 

O AK M35 B. ... $99 .00 STARG ATE 2000,,, $S3 .00 

ZENTTH $175.00 

M-D. Electronics will match or beat any 
advertised wholesale or retail price. 



Your best buys and warranties fur 
cable converters and descramblers 
start uitli a FREE catalog from Ml) 



EXCELLERATOR 

CABLE CONVERTERS 
WHEN QUALITY COUNTS 




For In form at ion Call 

402-554-0417 

To order or request a free catalog 

1-800-624-1150 



t $& mt *%* 






*> 
"B 



New Dynatrack™ fine tuning' provides unmatched picture quality 

S5& Mhz tuner provides S3 channel capacity 

Sleep timer for automatic shut off within 15-90 minutes 

2/3 switchable HRC / IRC ■■ Standard Switchable 

2 Year warranty, Last channel recall. Favorite channel select, Scan 

Double vented high efficiency transformer for cool performance 

Stargate^2001 $99.00 

Stargate-550XL $119.00 With Volume Control 

Don't settle for anything less. 



MmiEtmmmmms^ ffl 91 






C.O.D. 



875 SO. 72nd St. 

Omorw^NE 68114 



JYCWJOUNCCMLE TV tCATTTttlNTFECM UD ELEC7BONKS 71 IS PUKTt laSKI* 
AGREES TOCCMPLY WITH ALL STATE ANO E&CT RAL LAWS RfiCARULVCl ITUVATE 
OWSSHIPC* CAlLE TV EOLTPMOTT. IF YOU ARE UNSURE OF THESE IaWS 
CHECK WITH TOUR LOCAL OFFICIALS. 



CIRCLE 53 ON FREE INFORMATION CARD 



FREE cable and satellite descrambler plans. Send 
self addressed stamped envelope. MJM INDUS- 
TRY, Box 531, Bronx, NY 10461 -020B. 

HOBB Y.'b roadcasti ng/H AM/C B/surve i llance trans- 
mitters, amplifiers, cable TV, science, bugs, other 
great projects! Catalog $1.D0. PAN AXIS, Box 130- 
F9, Paradise. CA 95967. 

BUILD from simple materials, over 100 mites per 
gallon carburetor. Detailed plans, five versions. 
Good science project. $20.00 Visa welcome. (902) 
467-3577 VALLEY MICROWAVE, Station C, Bear 
River, N.S., Canada BOS 1B0. 



03 
O 

■z. 

& 

5 

id 
6 

< 



I'LL HAVE MINE 
DESCRAMBLED 




If you find a better deal, We'll beat 
Itl JERBOLD * TOCOM • HAMLIN • 

OAK ■ SCIENTIFIC ATLANTA • 

ZEWTTH • ask about our warranty 

program C.O.D. Visa, M/C, AM.EX. 

welcome. -FREE CATALOG 

• FREE CALL 

•OPEN SATURDAYS 

1 800 562-6884 

VLTJEO TECH 

3702 S. Virginia St. Ste. 160-304 

Reno, NV 89502 



INVESTIGATORS, experimenters — Quality new 
plans. Micro and restricted devices. Free catalog. 
Self addressed stamped envelope required. K EL- 
LEY SECURITY, INC. Suite 90, 2531 Sawtelle 

Blvd., Los Angeles, CA 90064. 

TELEPHONE caller identifiers. Displays incoming 
caller's telephone number, kit $49.95 postpaid, 
SURVEILLANCE catalog $5.00, EDE, POB 337, 
Buffalo, NY 14226. 

DESCRAMBLER kits. Complete cable kit $44.95. 
Complete satellite kit $49.95. Add $5.00 shipping. 
Free brochure. SUMMIT RE, Box 489, Bronx, NY 
10465. No NY sales. 



CABLE TV 

DESCRAMBLER LIQUIDATION! 



FREE CATALOG1 

Hamlin Combos S44, Oak M35B SS0 (mln. 5), etc. 



WEST COAST ELECTRONICS 

For Information: 818-709-1758 
Catalogs & Orders: 800-628-9656 



DESCRAMBLING, new secret manual. Build your 
own descramblers for cable and subscription TV. 
Instructions, schematics for SSAVI, gated sync. 
sinewave, (HBO, Cinemax, Showlime, UHF, adult) 
$12.95, $2.00 postage. CABLETRONICS, Box 
30502R, Bethesda, MP 20824. 

SMD How to use surface mounl technology. Build 
ultra miniature projects. Plans included free, infra 
red control, and an interesting light display. Send 
$15 00 to CHARLIE'S VIDEO, Dept, SRT, PO Box 
7782, La Sierra, CA 92503. 

HYPNOTIZE or Relax electronically! Alpha/medita- 
tion goggles. Complete kit $53.00. Free information, 
MARK WORLEY, Box 261113, San Diego, CA 
92196. 



SURVEILLANCE transmitter kits tune from 65 to 
305 MHz. Mains powered duplex, telephone, room, 
combination telephone/room. Catalog with Popular 
Communications, Popular Electronics and Ra- 
dio-Electronics book reviews of "Electronic 
Eavesdropping Equipment Design," $2.00, 
SHEFFIELD ELECTRONICS, 7223 Stony Island 
Ave., Chicago, IL 60649-2806. 



CABLE DESCRAMBLERS 
OAK M35B COMBO S39.95 



JerrolrJ, Zenith, Hamlin, Sci. Atlanta, Pioneer 
& MORE! OUR PRICES ARE BELOW WHOLESALE! 

CABLE-+- PLUS 

14417 Chase St. #481 -A Panorama City, CA 91402 

1-800-B22-9955 • Other Info. 1-818-785-4500 

NO CALIF. SALES - DEALERS WANTED 



BUILD subwoofers for home theater. $ave. Com- 
plete instructions $6.95 WILLIAM CROWLEY, 
2118 Wilson, Hollywood, FL 33020. 

PCB and schematic CAD. $195.00 IBM EGA CGA 
Multilayer, rubberband, autovia, NC drill, laser, dot 
matrix, plotter, library, Gerber, AUTOSCENE, 10565 
Bluebird St., Minneapolis, MN 55433. (612) 
757-8584 free demo disk. 

VIDEOCIPHER I l/scanner/cable/satellite modifica- 
tions books. Catalog $3.00. TELECODE, PO Box 

6426-RE. Yuma, AZ 85366-E426. 

DIGITAL recorder. Digitally record any audio 
source with special effects. Microprocessor con- 
trolled device. Detailed plans, $9.75: T. ZURAW, 
Box 341, Dearborn Hts, Ml 48127. 

REMOVE VCR copy protection, PCB PAL instruc- 
tions$16 50 w/P&H, LOGICAL CHOICE, Box 1256, 
Lomita, CA 90717. 

VCR repair kits. Free catalog: SMS ELEC- 
TRONICS, PO Box 0190, lompOC, CA 93436-0190. 

CALL display number of person phoning. Informa- 
tion on how it works, one chip circuit interfaces to 
computer, includes format, schematic, parts list, 
suppliers, Basic&C source, send $15,00 U.S. 
XANTHIC, 454 12th St. SW, Medicine Hat, AS, Can- 
adaT1A-4V1. 

TESLA coil. Completely solid state. Sparks over 15 
inches with 10 inch long coil! Plans $10.00 CORO- 
NA COIL, PO Box 474-D. Riverton. Utah 
84065-0474. 

TELEPHONE bug FM plans. Convert Radio Shack 
device easy, $8 00. ALLAN LABORATORIES, PO 
Box 14302, Research Triangle Park, NC 27709. 

TELECOMMUNICATION projects. 600 page de- 
tailed book. Modems, telephones, PCM's, switching 
systems, data, DTMF, more. $17.95 COMSPEC, 
200 Bay Street South. Box M3, Hamilton, Ontario 
L8P-4S4 Canada. 

LIGHTING — Complete portable lighting system 
perfect for stage lighting, exhibits, special events. 
Plans/application notes $5.50 ACS, 6220 Shal- 
lowford Rd. #152, Chattanooga, TN 37421. 

THE electronic defender an effective, non-lethal de- 
terrent to those who wish you harm. It will protect 
you and your properly. Detailed plans $6.95. Parts & 
PC board also available. TYLER ELECTRONICS, 
PO Box 493, Richmond Hill, NY 11418. 

KEYTRON amazing electronic keyhook, saves lost 
key problems, also reduces healing/ac bills, kit 
$19.95. Assembled $29.95, plans $6.00. Info pack- 
age $2.00 credited to firsl order. MERLIN TECH- 
NICAL COMPANY, Box 44213, Boise, ID 83711. 



BEST BY NAIL 

Ratal: Write National, Boa 5, Sarasota, FL 34230 



OF INTEREST TO ALL 



$48,900 INCOME and HAWAII 1 1 Free Report: 480(RE) 

Hawl, Hawaii, 96719. 

CASH LOANS UNSECURED to S1C,0O0, No Cred! 
Check, 1-800-3aB-B878, Dealer Inquiries Welcome. 
HAIR LOSS? INFORMATION about new trealmenls 

Pater Proctor, MO 1.60O-926.1752. 

VCR REPAIR - TECH NIC ANS' SECRETS REVEALED 
Do it yourself, literally save hundreds. Complete easy it 
follow manual. Includes 800 numbers of all majo 
manufacturers lor ordering parts direct 
SchemalicsJDiagrams. More. $9.95 to: ACME VCI 
REPAIR, 2104 Benwiok Lane, Aniioch. CA 94509. 



86 



WHY PAY SKY 

HIGH MONTHLY 

* RENTAL? * 



Pay down -to-ea rtli prices Tor cable TV 
descram biers. If you find a better deal, 
we'll beat it! • Hamlin • Jerrold • Oak 
* Sci entitle Atlanta * Tocom • Zenith. 

Ask about our warranty program. 

C.O.D. Visa, M/C, AM.EX. welcome. 

• Free Catalog * Free Call 

• Open Saturdays 

GTV 1464 Garner Station Blvd. #315 
Raleigh, NC 27603 

1 800 328-0198 



SATELLITE TV 

FREE catalog — Lowest prices worldwide. SKYVI- 
SION, 2009 Collegeway, Fergus Falls, MN 56537. 1 
(800) 334-6455. (See full page ad in The Shopper 
section) 

VIDEOCYPHER II descrambling manual. Scht> 
matics, video and audio. Explains DES, Eprom, 
Clonemaster, 3 Musketeer, Pay-per-view (HBO. Cin- 
emax, Showtime, adult, etc.) £16.95, £2.00 postage. 
Schematics for Videocypher Plus. S20.00. Sche- 
matics lor Videocypher 032, S15.00. Collection of 
software to copy and alter Eprom codes. £25.00, 
CABLETRONICS, Box 30502R, Bethesda, MD 
20824. 



CABLE TV Secrets — the outlaw publication the 
cable com panies I ried to ban . HBO, M ovie C h annel , 
Showtime, descramblers, converters, etc. Sup- 
pliers list included. £9.95, CABLE FACTS, Box 711- 
R, Pataskala. OH 43062. 

FREE catalog — Compare our prices for new sys- 
tems and upgrades. Latest receivers and dishes — 
all top brands. ALPHA SATELLITE DIST, PO Box 
197A. Hawthorne, NJ 07507-0197. 1 (800) 535-AL- 
PHA. 




ANNOUNCING: 

AN END 

TO 

HIGH MONTHLY 

CABLE FEES! 



All Jerrold, Oak, Hamlin, Zenith, Scientific At- 
lanta, Magnavox and all specialized cable equip- 
ment available for shipment within 24 hours. For 
fast service MC/VISA or C.O.D. telephone or- 
ders accepted. 60 Day Guarantee (Quantity Dis- 
counts). Send self -addressed Stamped enve- 

l0 ^ 1-800-232-5017 

WW COD. ORDERS 

L^™ ACCEPTED 



CABLETRONICS, INC. 

1304 E. Algonquin Road Suite 501 
Algonquin, Illinois 60102 



mmmmmmmmmmm 




A -f leetrBiiirj Qr JSC 



mmmmm mmmmmmm 




Your Ticket To 

SUCCESS 

Over 28,000 technicians have gained admit- 
tance worldwide as certified professionals. 
Let your ticket start opening doors for you. 

ISCET offers Journeyman certification in 
Consumer Electronics, Industrial, Medical, 
Communications, Radar, Computer and 
Video. For more information, contact the 
International Society of Certified Electro- 
nics Technicians, 2708 West Berry Street. 
Fort Worth, TX 76109; 1817) 921-9101. 



Name 

Address 

City 

State 



Zip 



Send material about ISCET and 
becoming certified. 

Send one "Study Guide for the 
Associate Level CET Test 



En- 



closed is $10 (inc. postage). 



MARK V €L€CTRONICS, INC. 

Competitive Pricing * Fast Shipping Since 1985 



ORDER IN CALIFORNIA 800-52 1 -MARK 
ORDER OUTSIDE CA 800-423-FIVE 
FREE CATALOG & INFORMATION (213) 888-8983 
FAX (213) 888-6868 



▲ indicates the level of difficulty in the assembling of our Products. A Beginner AA Intermediate AAA Advanced * 




Fully Assembled 

TA-1000A 




Due iq this specral oiler £ low price we can only oxefianoG or repair any ol Irrase units (TA-36QO, TA-477 TA-802 

& TA-tOOOA} within 1 S days or your receipt. 

rr-.e above prices are tor ih» complesa sals For separate unit pckM. please see below "Transformer 



AMPLIFIERS 



KIT ASSEMB. 



MISCELLANEOUS 



KIT ASSEMB 



MODEL 
IA-28MK2 

TA-50A/6 

TA-50C 

1A-120MK2 

1A-3Q0 

SM-302 

TA-323A 

TA-377A 

TA-4W 

TA-477 

1A-8O0MK2 

TA-802 

TA-1000A 

TA-1500 

1A-2J00 

TA-24O0A 

1A-2500 

TA-2B0O 

1A-30OO 

TA-3S0O 

sum 

S ',1-328 
5M-333 
SM-66G 
SM.E33 



DESCRIPTION 

Digilal Voice Memo AA 

Mul 1 1- Purpose Melody GeneratDt A 

Mulh.PuipMe Melody (Happy Binhday Wedding March. elcl Generator 

35W Class "A' Mam. Power Mono Amp. A A . . . .. 

30W Mulli-Purpose Single Channel Amp A — , 

SOW r SOW Stereo Power Amplilier |wilh Mir. input) A A 
SOW * 7 Slereo Pfe-main Amp A 



Stale ol lire An Fully Complementary Symtnelrical F£T Pit-Amp AAA 

sow Solid Slaw Mono Amp a _ 

120WMos1et Power Mono Amp. AA __,.. 

120W t UOWlow Tim Pte-Mim Stereo Power Amp AA 

SOW * 30W Pure DC Stereo Mam Power Amp AA 

IMW Dynamic Class "A" Main Power Mono Amp AA . 

ItBW X 2 Class "A' DC Stereo Pre- Mam Amp AAA 

DC Fet Super Class "A - DC Pie-Amp AAA „, „ , 

EteclTOn.'t Echo fi RevereeratioriA Tip * .. 

HO Pre-Amp w: 1 0a nd graphic equalizer * 
61-FET IC Pre-Amp w/3 way lone control A A . 



5 30 05 
.. 12.64 
A 13 66 
. 31 50 
. 20 00 

67.00 
.3150 

59 95 
..26 00 
..68.00 

63.92 

15 94 
.50.09 

73 TO 
. 47.70 



Stereo Simulator (for Mono TV or Any Mono Source) AA 

30QW HO Hi-Fi Power Motto Amp AAA 

7 Band: HI-FI Graphic Equalizer a a a 

4 Channel Protessionat Color Light Controller* 

AuOioAtideo Surround Sound Processor AAA* 

Dynamic Naise Red lc tier. A 

universal Audio/Video KAflAQKt Mixer Pre-Amp. * 



46.90 
.27 00 

65.60 



65 00 

76 00 



17,20 
11.71 
42.60 
3- at 
7600 
42.80 
7S00 
34 93 
65.00 

59.7! 
"BOSS 
95 81 
5S24 
9609 

Eaao 

6357 

35.50 
110.00 

3SSII 
145.00 

■5 on 
34.00 
225 00 



MODEL 

TY-23B 

TY-25 

TY-35 

TY-36 

TY-38 

■■ -■'-•• . 

ly-4! 

TY-43 
TY-4S, 

TY-47 
lO.OOOufl 



DESCRIPTION 

3 Channel Color Liphi Controller * 

Stereo Loudspeaker Prelector A .. . 

FM Wrreiess Microphone A 

ACrDC Quartz Digital Clock A 
Sound / Touch Control Swilch A 



Inlrareo flemole Conlrol Unit |w.'Caset A A A 
8ar I Dot Level Meier a a 

3'vDigilal Panel Meier A 

.■0 Sleps Bat t Dm Audio Level Display AA 

Superior Electronic Roulette AA . .. , 

80 V Capacitor (Suggested lor TA-3600. TA-477. TA-iOOOA & TA-802] . 



..14.B5 
..11.26 
13.00 
1200 
22 00 
..24.15 
29.00 
39.45 
19.46 



S 65.00 
20 95 

2E20 

35 00 
33 81 

36 00 
46.14 
27.24 
23.00 



REGULATORS 



KIT ASSEMB, 



TB-355A 0-15V 5A Bejufflea DC Power Supply mo case 6 x'lotmer] A SIS 65 S II 76 

TH-3S5B O-30V 3A BegutalKJ DC Power Supply mo case a xlormeri A . .15 65 21.75 

0-50V3A Regulated DC Power Supory ino case S xlormertA a 16.7S !3.65 



METAL CMINETS WITH ALUMINUM PAHEl 



MODEL 
LG-1273 
LG-16J4 
LG-1924 
LG-I9J5 



rTiVT i D- MATCHING 

TA-280O.TA-377A, 1A-22O0 
TA-323ATA-377ATA-220O.. 



r 

8' 

I1H TA-802 1A.15O0.TA110MK2.TA-80OMia. TA-IOOOA 

11H TA-477, TA-atJO. MK2. TA-150O. TA-IOOOA. TA-3600 

r TA-377A IA-2800 1A-22O0. IA.I20M«2 



PRICE 
S2365 

27 50 
.. 33M 

. 35 80 
... 29.25 



POWER TRANSFORMERS 



DIGITAL METERS AND COUNTER 



KIT ASSEMB. 



SM-43 

SM-43 

SM-48A 

SM-49 

SM-100 



it Mull, functional Led P M iwABS rustic casi). 
t .■ Hr-Precisiorr B ? M A A A 
4-.. Hi -Precision D P M. |w/ASS plaslie caiekAAA 
i-t Mulh-furiclionil LCD D M P (w-'Hold FunclnmlAA . 
tSOVC Dig Jit Frequency Counltr AAA 



S34 50 

38 00 
41 20 
3600 
79 00 



S43 00 
48.00 
52 00 
44 50 
90 00 



MODEL 
001 

m 

333 
KM 

035 

B06 



DESCRIPTION 

25V X 2 6A to 30V 1 2 BA 

36K X 1 3A 

40V 1 2 6A 

24Vi26A 

2EV«2 3A 



MA - :.!' \r- PRICE 

TA-600 MK2, TA-802 TA-620A. TA-1D0OA. TA-1500 . S 27 00 

TH-S03, TA-323A. TAJOO, TA-300. TA-377A 22 00 

TA-477 29.00 

TA-120MK! 22 03 

TR-355B 16.00 

TR-355A 15.50 

IA-3600 43 00 



09 

rn 
■o 
H 
m 

m 

m 
3 



Wy jcxep* m^jr Cirms.l Cardi . J,toftir OWwns. Chaclii and C.O.D OrdoraCO-tJ frt^SSOO. S^mumcftJwrjS^W.-WejnflbrUPSgrt^n^ $3 M) and ttop Oy US ma* BuStrtfc*SS &■ ShOwrODlTl hOurS: (FaCHlC Time) 

Oijn4tlJS i^AjWaUGrijrHtfeniMpiulm *AHa5Si>mWEfliiniriiiivni«a3QdjyiWjTtfriir^ Mofl. ItlfU Ffi. 9'30 am 10 5-00 pTtl 

■QtC-Ap*aE*aMSdia-ie4tai.6 79% < AJi mgtt-Jiam i-tg £ fnrcbj tern tul^a to p*<sf Uf Pkch i'esu!D|«tiU tficf^wft^pi^ Snl 10:00 am 10 5:00 pm 

MARK V ELECTRONICS, INC. - 8019 E. Slauson Ave, Montebello, CA 90640 SSl^jl 



CIRCLE 93 ON FREE INFORMATION CARD 




WE HAVE THE MOST" ADVANCED 
TECHNOLOGY IN CABLE EQUIPMENT: 

• BASE BAND • JERROLD 

• PIONEER • TOCOM 

• HAMLIN • ZENITH 

• SCIENTIFIC ATLANTA • DAK 

For out of this world prices call 
WORLDWIDE CABLE 

1800-772-3233 

FREE CATALOG AVAILABLE 

7491 05 N. FEDERAL HWY., SUITE 142 
BOCA RATON, FL 33487 

iS8| /COD/Uia N0RDROAS4U3 



CIRCLE 191 ON FREE INFORMATION CARD 



O 

Z 

O 

cr 
r- 
o 

LU 

_l 
LU 

6 

< 

DC 

88 



3 FORI 
SPECIAL 

ON SUB-MINIATURE VOICE 
FM TRANSMITTERS. 

KITS CONTAIN PC BOARDS 




-FMX-1 LONG RANGE{3MI) ULTRA SENSITIVE 
FM VOICE XMTR with fine tuns, range control 
plus $34.50 




•TELX-1 TELEPHONE FM XMTR (3 Ml} auto- 
matically operates when phone is used. Crystal 
clear clarity with fine tune and range control. 
Non detectable S34 50 



^PWK««« ; ■■■' 

*ATR-1 AUTOMATIC TELEPHONE RECORDING 
DEVICE tapes telephone conversation all 
automatically $19.50 



ALL THREE OF ABOVE FOR « SS9.50 



CALL OR SEND VISA, MASTER CHARGE, 
MONEY ORDER, ETC. TO AMAZING CONCEPTS, 
BOX 716. AMHERST, NH 03031. (603) 673-4730. 



CABLE TV 
"BOXES" 

Converters-Descramblers 

Remote Controls-Accessories 

* Guaranteed Best Prices * 

* 1 Year Warranty - C.O.D.'s * 

* Immediate Shipping* 

+ FREE CATALOG + 
Call or Write 

NAS/TRANS-WOBLD CABLE CO. 

3958 North Lake Blvd. • Suite 255 

Lake Park, Florida 33403 

1 -800^42-9333 

1 -800-848-3997 



DO It yourself, systems, upgrades, major 
brands discounted, save 30% — 60%. Lowest 
prices anywhere. L.J.H, INC., call Larry at (609) 
596-0656. 



WANTED 

INVENTIONS/ new products/ideas wanted: call 
TLCI for free information 1 (800) 468-720024 hours/' 
day -USA/Canada. 

INVENTORS: We submit ideas to industry. Find out 
what we can do for you. 1 (800) 288-lDEA. 



TUBES - 2000 TYPES 
DISCOUNT PRICES! 

Early, hard-lo-fwd, and modern tubes. 
Also transformers, capacitors and 
parts for tube equipment. Send $2.00 
for 26 page wholesale catalog. 

ANTIQUE ELECTRONIC SUPPLY 

6221 S Maple Ave. •Tempe, AZ 852S3 -602/820 -5411 




INVENTORS! Your first step is important. For free 
advice, call ADVANCED PATENT SERVICES, 
Washington, DC, 1 (800) 458-0352. __ 

THAVEL! High income! Radio officers wanted lor 
shipboard employment. Must have FCC second 
telegraph license. Rae Echols, AMERICAN RADIO 

ASSOCIATION, 5700 Hammonds Ferry, Linthicum. 
MD 21090. 



BUSINESS OPPORTUNITIES 

MAKE S50/hr working evenings or weekends in 
your own electronics business. Send for free facts. 
MJME INDUSTRY, Box 531, Bronx, NY 
10461-0208. 

YOUR own radio station! Licensed /unlicensed AM. 
FM, TV, cable. Information $1.00. BROADCAST- 
ING, Box 130-F9, Paradise, CA 959B7. 

LET the government finance your small business. 
Grants/loans to $500,000. Free recorded message: 
(707)449-8600. (KS1). 

MAKE $75,000 to $250,000 yearly or more fixing 
IBM color monitors (and most brands). No invest- 
ment. Start doing it from your home. (A telephone 
required.) Information, USA, Canada $1.00 cash. 
US funds, other countries $8.00 RANDALL DIS- 
PLAY, Box 2168-R, Van Nuys, CA 91404 USA. 

RECESSION? Thriving fully equipped audio/video 
repair shop. $130K + this year! Proven 40%+ gross 
last three years. $70,000.00 cash. AUDIOTECH, 
256-BNorthHighway101,Encinitas, CA 92024. Fax 
(619) 944-0345, Phone (619) 944-9048. 



[Great money in VCR repair!] 

Home si u dy. Le a r n h ig h-p rot 1 1 re pairs 
_ without Investing In high-tech instruments 
| FREE BOOKLET! E0G-223-4542. 

I Name 
Address ■ •;■ . 



City. 



.Zip- 



I The School of VCR Repair, 2245 Perimeter |^ 
■ Park, Dept. VK342 , Atlanta, Georgia 30341 I 




ELECTRONIC 
ASSEMBLY BUSINESS 



Slarl home spare lime Investment knowledge or 
experience unnecessary. BIG DEMAND assem- 
bling electronic devices. Sales handled by profes- 
sionals Unusual business opportunity. 

FREE: Complete illustrated literature 

BARTAR.E00Bux248 

Walnut Creek Calif 94S97 



EASY work! Excellent pay! Assemble products at 
home. Call for information (504J 641-8003 Ext. 5192. 

MAKE $$$! Become an American electronics deal- 
er! Profit opportunities since 1965. Call SCOTT 
PRUETT, 1 (800) S72-1373. 

HOME assembly work available! Guaranteed easy 
money! Free details! HOMEWORK-R, Box 520, 
Danville, NH 03S19. 

RECOVER pure gold from scrap circuit boards, 
electronic parts. Easy methods. Send $5.00, RECY- 
CLING, Box 11216PE, Reno. NV 89510-1216. 



CABLE DESCRAMBLERS 

Stop pay En g rental fees I 

ONE YEAR WARRANTY 3D DAY MOMEY BACK GUARANTY 

Extended Warranties ■ Free Tech Support Service 

We Welcome Canada - Hawaii - Atasha 
Monthly Dealer Specials 



Panasonic « Zenith ■ Oak ■ Hamlin 

Jerrofd - Starcom 7 * Etc. 
Dealers Wanted - Quantity Discounts 

COD's - VISA - MasterCard - Discover 

Alt Orders and Free Catalogs 

(800) 234-5552 

211? Hollywood Btvd,, Ste.lCS, Hollywood. FL 33020 



ZENITH & TOCOM SPECIALS 

SUPER Zenith (Z-TAC) converters (w/flash- 
guard)... $179.00. Zenith "turrt-on" module... 
$49.00. Tocom 5503(A) converters. Call. Tocom 
(55u3-VIP/5503{A)/5507) "turn-on" chips. .$49.00. 
Tocom 5507 & Jerrofd (security screw removal 
tool)...$22.00. CfNEPLEX VIDEO GROUP. 1 (800) 
726-4627. 



INVENTORS 



INVENTORS! Can you patent and profit from your 
idea? Call AMERICAN INVENTORS CORP. for free 
information. Serving inventors since 1975. 1 (800) 
338-5656. 



LIGHTEN UP. 




High-fat, high-cholesterol foods can leave 
you with a heavy heart. 

^American Heart Association 



FREE CATALOG! 

1-800-648-7938 

JERROLD HAMLIN OAK ETC 

CABLE TV 



Special Dealer Prices! 
Compare our Low Retail Pricesl 
Guaranteed Prices & Warranties! 
Orders Shipped Immediately! 

REPUBLIC CABLE PHODUCTS, INC. 

"3 4080 Paradise Rd. #15, DeptRE891Cn 
3 Us Vegas. NV 89109 l~ J 

For all other information (702) 362-9026 



ALARM SECURITY 

LOW cost burglar alarm systems for your home, 
business, auto, computer, and personal. We carry 
all lines of security and electronics supplies. Full 
information package send $5.00: APS, Box 1074, 
Moorhead, MN 56561-1074. Inquiry (218) 
236-6426. 



CONVENTIONS 

THE Greater Louisville Hamfest and Comput- 
er Convention. Saturday, September 28, and 
Sunday September 29, 1991. New and used 
equipment, forums and testing. For addi- 
tional information write Post Office Box 
34444-R, Louisville, KY 40232-4444 or call 
(502) 964-1132. 



DESCRAMBLERS 



CABLE TV EQUIPMENT 




CALL TOLL FREE 

1-800-228-7404 






OUBPfiOOUCIS* 

PROOF 



30 DAY 

vcmven 

etwpr 

you wan no m wm m cw W5MB 

WE CARfY All MAJOR WAND5 

BEST PRICE BEST 

THE CONMHUOM 

FOR MORE NFORMAnON 

CALL OR WRITE 

1-512-250-5031 |l 




•11* ULCOfW WOOD 1 
'JjgJBJg HMg TBtjj ;i7tt 



EDUCATION & INSTRUCTION 

F.C.C. Commercial General Radiotelephone li- 
cense. Electronics home study. Fast, inexpensive! 
"Free" details. COMMAND, D-176. Box 2324, San 
Francisco. CA 94126. 

COMPLETE course in electronic engineering. Eight 
volumes. Includes all necessary math and physics. 
Free brochure. BANNER TECHNICAL BOOKS 
1203 Grant Avenue, Rockford. IL 61103. 



Start Your Own TV/VCR 
♦ Repair Business -*- 

Now you can train al home in your spare lime for a money- 
making career as a TVVCR Repair Specialist. No previous 
experience necessary. No need to qui! your |0b or school Every- 
thing is explained m easy-lo-undetstand language wilh plenty of 
drawings, diagrams and pholos We show you how lo trouble- 
shool and repair videocassetle recorders and TV sets, how to 
handle house calls and strap repairs tot almosl any make of tele- 
vision or VCR. Toots are included with your course so you can gel 
"hands-on" practice as you follow your lessons step by step. 
Send far free facts atraul the exciting opportunities in TV,' VCR 
Repair and find out how you can start making money in your own 
business! MAIL COUPON TODAY! itn 



ICS! SCHOOL OF TV/VCR REPAIR, Dept. ADEDB1S 

'."" ""J 925 Oak Street. Scranton. PA 18515 
Please send me full information and color brochure on how I 
can learn TV.VCR Repair at home in my spare time. I under- 
stand there is no obligation and no salesman will visit me 
Name Age 



Address . 



City/SIa la/Zip _ 
Phone f ) . 



. Apt. # . 



VIDEO tapes by a college instructor covering the 
analysis of DC/AC circuits, transistors, integrated 
circuits, and microprocessors. Send for free demo 
tape. Add $2.50 for P/H. OCS, PO Box 292 Fort Mill, 
SC 29715 

LEARN lundamentai electronics call 1 (900) 
988-9808 ext 684. Your phone bill rate $2.00 per 

minute. 



BIOMEDICAL ELECTRONICS 

BIOMEDICAL letter covers medical electronics, 
anatomy, equipment functions, electrical safety, 
troubleshooting. PNP PUBLISHING, Box 333, 
Brooklyn, NY 11204. (718) 837-9349 extention 55. 



^ 



# 





12" Subwoofer Box 12" Pioneer Subwoofer 800 Hz Horn 



(HJ PIONEER" 

12" super outy. dual voice coil 
subwoofer. 30 oz. magnet. 2" voice 
coil. 100 watts RMS, 145 watts man 
power handling capability. 6 ohm 
impedance (4 and a ohm. compatible). 
Sensitivity; 89dBiW/iM Response: 
25-700 Hz, QTS. .31 , VAS. 10.3 GU ft. 
Net weight: 6 Ids, Pioneer #A30GU30-55D 

#RL-290-145 $39 80 $36 80 

(1-3) (4-up> 



18" Eminence Woofer 



The perfect high volume cabinet 
for dual voice coil subwoofers. 
Sox comes with pre-cul wooler 
and port holes. Cabinet volume: 
2 cu. ft. with dual ports. Charcoal 
carpet. Dimensions; 13" (H) x 13" 
(D) f 30" (W). Net weight: 29 lbs. 



Piezo midrangertweeter driver unit. 
Response: 800-20 KHz. Power handling 

capability: 20-30 volts (approximately 50 
waits RMS). Sensitivity: 93 dB. 2.83W1M. 
4" round Motorola *KSN 1086. 



#RL-260-495 



$59 



90 

Each 



#RL-270-085 $25 30 

(1-3) 



$23 



95 



Professional driver 
lor use in auditorium 
and studio sound 
sysloms. Giant 100 
oz. magnet. 250 
watts RMS. 350 
watts max power 
handling capability. 
fs. 30 Hz, QMS= 
3.17, OES=. 373, 
QTS= .33. 
VAS. 10.5 cu ft 
SPU95dB1W/1M. 
Net weighl: 29 lbs. 



( 



i 



(4-up) 



EMINENCE 

#RL-290-200 $99 B0 $93 40 



H'Upl 



12" Pyle Woofer 



5-1/2" Cone Midrange 






Gw 



PYLE 



12*. 70 oz. magnet woofer. 2-1/2" voice 
coil. 105 watts RMS. 155 watls max 

power handling capability. 



#RL-292-050 




$59 80 

(6-up) 



Original Sanyo high 
end system midrange, 
Large 5" paper cone 
with gold took dust cap. 
Heavy 12oz. magnet. 
1" ferro Huid cooled 
voice coil. 50 watts 
RMS. 75 watts max, 
Sanyo pari #S12HlO. 
Net weight: 1-1/2 lbs. 

#RL-2S1-100 



f 



SASYO 

$5- $3 95 

(1-9) (10-up) 



Subwoofer Crossover Network s-^ i-n> 

NEW A 
revised j 
catalogV^ 



Super duty, 200 watt RMS 
power handling capability. 

Designed specially for duat 

voice coil subwoofer 

systems. 12 dS per 

octave roll-off al s%t ^^ 

150 Hz inlo 8 ohms. 

Crossover also fealures 

a set of oulpuls 

for use with your existing speaker system. Network is 

totally passive, requiring no power source of its own. 



X NEW J^ 
$ BEVESED -f 
-^VCATALOG^ 



#RL-260*220 



$28 B0 

(1-5) 



$24 



95 




(8- up) 



f^p^tS 5 ** 



\ 



340 E. First St.. Dayton, Ohio 45402 
Local: 1-513-222-0173 
FAX: 513-222-4644 



■15 day money back guarantee ■ SI 5.00 minimum order • 
We accept Mastercard, Visa, Discover, and C.O.D. orders. ■ 
24 hour shipping ■ Shaping charge - UPS chart rale + 51,00 
[53.00 minimum charge) • Hours 8:30 am - 7:00 pm EST, 
Monday - Friday ■ 9:00 am - 2:00 pm Saturday. Mail order 
customers, please call for shipping estimate on orders exceeding 5 lbs. 
Foreign customers please send $5.00 U.S. funds for catalog postage. 



CALL TOLL FREE 
1-800-338-0531 




FREE 
CATALOG 



Co 

m 



00 

m 

33 



oo 



CIRCLE 56 ON FREE INFORMATION CARD 



89 






,e*ice 



sot >™- 






Of PNW 






Welcome to. . . 




„ to FVeteots 



SCIENCE 




The /Imateur Scientist's Journal 

Embark on art irresistible new journey into the realm 
of mystery, challenge, and exploration! The perfect 
magazine for the budding scientist, the serious 
amateur, the professional who would like to relax, 
and those who simply want to gaze at the stars. 



Science PROBE! — the only 
magazine devoted entirely to Amateur 
Scientists! If you are fascinated by sci- 
ence in all its many forms ... if you can't 
stay away from a microscope, tele- 
scope, calipers, or test tube — we in- 
vite you to share the wonders in every 
issue of Science PROBE! You will join 
a community of Amateur and Student 
Scientists who enthusiastically seek 
scientific knowledge or follow scientific 
pursuits for their own sakes and not 
merely as a profession. 

Obtain your next issue of Science 
PROBE! by visiting a quality News- 
stand, Convenience Store, or Super- 
market or by reserving your personal 
copy through the mail by completing 
the coupon beiow. 

From your very first issue of Science 
PROBE! you will be involved in a world 
of scientific facts, experiments, and 
studies pursued by amateur scientists 
who are university students, investors, 
academicians, engineers, or office 
workers, salesmen, farmers — whose 
quest is to probe into the mysteries of 
science and reveal them to all. 

Plan to become a Science PROBE! 

reader! 



Articles to appear in upcoming issues of Science PROBE! 



are: 



How an Amateur Mapped the Milky Way 

Make your own Seismometer 

Operate a Solar-powered Weather Station 

Grow Crystals Automatically 

Experiment with a Saltwater Aquarium 

How to Keep a Science Notebook 

If you're fascinated by science in all its many forms, 
if you are compelled to experiment and explore, then 
Science PROBE! is your kind of magazine! 



Science PROBE! 

500-B Bi-County Boulevard 
Farmingdale, NY U735 

Please forward ray copy of Science PROBE! as soon as it comes off the press. 
I am enclosing $3.50-U.S.A_ ($4.23-Canada-includes G.S.T.) plus $1.00 for 
shipping and handling. Better still, please enroll me as a subscriber and send 
the next four (4) quarterly issues of Science Probe. I am enclosing $9.95- 
U.S.A. (Canada: $16.00— includes G.S.T.) 

D Next Issue Only D Next Four Issues (1 Year) 
Offers valid in the U.S.A. and Canada only. No foreign orders. 
Name 



I 

. 
I 

I 

| City . State . 

| All Orders payable in U.S.A. Funds only. 
I 



Address . 



_ZIP, 



7RJ11 



ON SALE AT QUALITY NEWSSTANDS, CONVENIENCE STORES AND SUPERMARKETS 
GET YOUR COPY TODAY— $3.50-U.S.A.— $3.95-Canada 



We Have QUALITY PARTS • We Have DISCOUNT PRICES - We SHIP FAST 



m<imffl&m<@m 



'ighest Quality Metal Cassettes (Erased) 



nlum quality metal tape In C-6G and C-9Q cassettes (30 or 
iin r par side). One of the finest "brand- name* [apes on the 
we. in durable, clear plaslic transport mechanisms. Recorded 
bulk erased , the record- protect labs have been removed and 
store , n eed 10 be taped over to re- reco rd . Aud bphiles wi IE 
reciate the wide dynamic range of this tape. If your cassette 
< has a "metal" setting you will hear Ihe difference. A real bargain 1 
nh. lape-CAT#C-6QM $1.25 each* 10 for $10,00 
nin. tape - CAT* C-90M 11,65 each* 10 for $15.00 

tSSETTE STORAGE CASE 

:K unbreakable plaslic audio cassette storage case. 
f#CBOX 5 lor $1.00 - 100for$15.00 



OCZ30 



TOUCH DIMMER 




m connected 1o any lamp, will turn It 
and oil and change the brightness 
i\ when any metal pan Is touched. We 
■t have ihe wiring harness that orfgi- 
y connected this to the lamp, bus we 
i provide a simple hook-up diagram 
I Instruction sheel. The solid-state cir- 
;ry is contained in a thermo- 
stebox 1.91" X 3.11" X0.B35V 
CAT#PMR-1 S3. 50 each 



ELEPHONE KEYPAD 



button telephone 
/pad. Ivory finish. 
irx2.2-x0.58" thick. 
■Erix encoded, 
sal tor telephone or 
:urily keypad. 
iT#KPT-t $1.00 each 



DOB, 
EBBS 

bbb' 



10 tor $9.00 



OPTO-SENSOR 



IW/Optron * OPB5W7-2 
emltter^sensor pair In 
»ct angular package with 
f color coded leads. 
VWOSFM 2 tor f 1.00 



UL TRASONIC CERAMIC 
CROPHONE/TRANSDUCER 



L.E.D.'S 



Standard JUMBO 

Diffused T 1-3/4 size {5 mm) 



RED CAT* LED-1 

1 lor $1 .50 ■ 100 for $1 3.00 

CREEH CAT#LED-2 

10 lor $2.00- 100 for $17.00 

YELLOW CAT* LED-3 

10 tot $2.00 ■ 100 lor $17.00 

FLASHING LED 

W.' buitt in Hashing circuit 
5 volt operation. T 1 -3/4 

RED $1.00 each 
CAT* LED -4 10 for $9.50 

GREEN $1.00 each 
CAT# LED-4G 10 lor $9 50 

YELLOW $1.00 each 
CATXLED-4V 10 for $9.60 

LED HOLDER 

Two piece holder. ** & 

CAT* HLED 1-0 for 65c 



RECHARGEABLE 
BATTERIES 



ff 



masonic (Matsushita) 
EFR RCBK40K54 
i urtrasonic microphone 
insisting o( ablmorph 
pe piezoelectric ceramic 
srator. Ideal for burglar alarms, auto 
»r openers, flow rate detectors and re- 
de control systems, Norn. Free,. 40kHz. 
tax Input volts; 20 Volts, 15/16" rjta X 
'B" high. SIB" long leads. 

CAT#UST-1 $1.00 each 



AUDIO SLIDE POT 



Jual IK audio. 

■ \l? long, 2 1/2- slide 

:at#asp-ikd 

leduced lo 50c each ■ 

100 for $40.00 



Nickel-Cad 



AAA SIZE $1.50 each 
1 .2 volls 1 B0 mAh 
CAT# NCB-AAA 

AA SIZE $2.00 each 

1,25 volts 500 mAh 

CAT* NCB-AA 

AA SI2£ $2.20 oach 

WITH SOLDER TABS 

CAT* NCB-SAA 

C SIZE $4.25 each 

1.2 volts 1200 mAh 

CAT* NCB-C 

O SIZE $4.50 each 

1.2 volts 1200 mAh 

CAT* HCB-D 




INFRARED SECURITY LIGHT (AS-tS) 



Electriko 9 SlL-101 - Experiment wilh infrared sensors with 
Ihese outdoor security lights. Contain tots of inieresting 
components, an IR detector, pholoresisior, relay, 
transformer, ICs, voltage regulator, capacitors, trimpots 
and other goodies. Returned to ihe distributor for variety 
ol reasons, we've lound I hat mosl of them work to some 
extent. We don't want to test them and would prefer lo 
sell them "as-is* at a greatly reduced price. Mounts to any 
standard electrical junction box. Infrared sensor delects 
movement up lo 65 feet and turns on lights. Sensor can be 
adjusted for sensitivity and duration of lighting. The position 
of Ihe sockets and Ihe Inlrared sensor can be easily adjusted. 
Will handle two 150 watt PAR 38 lamps. Suitable for wet locations 
Bulbs not included .CAT* IL-1Q1 $750 each 




\24 PIN ZERO INSERTION] 
FORCE SOCKET 




Tex tool # 224-3344. Protect 24 pin dip ICs 
Irom damage during test, burn-in or pro- 
gramming. Lever- operated mechanism 
Jocks pan securely in place and releases it 
with no damage to component leads. 
CAT#ZJF-24 $4.50 each 



FLASH ASSEMBLY 






New compact flash 

assemby from a 
U.S. manufacturer ol 
cameras. Operates 
on 3 Vdc and measures GrXCEU-T 
2 1/Tx 1 1/4 - . Ideal for 
use as a strobe, warning light or attention 
getter. Includes hook-up diagram. 
CAT#FSH-1 $3.75 each 
10 for $35.00 -100 for $325.00 



HALL EFFECT SENSORS 



Microswilch *SS41 
Tiny, solid stale switch 
reacts instantly to 
proximity of magnetic fietd. 
Operates at extremely high speeds, up lo 
1 00 khz. Case size: 0.1 2" X 0. 1 7" X 0.06 - 
thick, 4.5 Vdc to 24 Vdc supply voltage. 
10 ma. sink type digital output. Operating 
gauss - 15 lo40. P.C. leads. 
CAT* HESW-2 75e each - 10 lot $6.50 
100 tor $60.00 • 1000 for $500.00 

Sprag u 8 » UGN3075LT \~ \ . ... 

Operates on 4,5 - 24 Volts 

Can sink 10 ma. Wilh suitable output putl 
up, can be used directly with bipolar or 
CMOS logic circuits. Especially suited for 
electrons commutation in brushtess D,C. 
motors using mutlipie ring magnets. Very 
liny surface mount package 0, 1 75" X 

0.09"X 0.06 - thick. 

CAT#HESW-5 2 lor $1.00 
1 DO for $4 5.00 Large q u anta i es available 



Miniature Toggles 

Rated: 3 amps @ 120 Vac 

S.P.D.T. (ON-Off) 
solder lugs 

CAT* MTS-4 

$1 .35 each Jf. 

10 lor $12.50 *, 

100lor$110.00 M6 

S.P.D.T. (OH-OH) 
P.C. mount 

CAT*MTS-4PC $1.00 each 
10 for $9.00 - 100 lor $80.00 

D.P.D.T. (QH-ON) 

solder logs 

CAT#MT&J $1.75ea. 
10 lor $15.00 

D.P.D.T. (ON-ON) 

P.C. mount 

CAT* MTS-SPC $2.00 ea. 

10 for $17.50 

Pushbutton Switch 

SMK 

Manulacturlng 
0.47- square 

black pushbutton. 
SPST normally 
cpen. 4 p.c. pins 
for mounting. Ideal for low 
current switching applica- 
tions. CAT#PB-29 
5 lor $1.00- 100 for $15,00 



PHOTOFLASH 
CAPACITOR 



Rubicon CE 
210 Mfd 330 Volt 
photoflash 
capacitor, 
0.79-dia. X 1.1" high. These 
are new capacitors that have 
been popped wNh 1.4" black 
and red wire leads soldered 
lo the terminals. 
CAT* PPC-21Q 
$1.25 each- 10for$11.00 

100for$1CO.OO 

Large quantities available. 

Call for pricing. 




L.ED. FLASHER KIT 

Two LED. s flash In ^14, ^ lt 
unison when a 9 volt 
battery is attached. 
This kit includes a 
p.c. board, all the parts 
and instructions lo make a simple flash- 
er circuit. A quick and easy project tor 
anyone with basic soldering skills, 
CAT#LEDKJT $1.75 per kit 

LE.D. CHASER KIT 

Build this variable 
speed led chaser, 
lOleds flash 
sequentially at 
whatever speed 
you set them for. 
Easy to build kit includes pc board. 
parts and ins! ructions . Ideal lor special 
lighting effects, costumes, etc. Oper- 
ates on 3 to 9 volts. PC board is 5* X 
2.25". A great one hour project. 
CATtfAEC $6.50 each 

STEPPING MOTOR 
CONTROLLER KIT 

Learn about 

stepping 

motors while 

building 1 his 

Simple circuit. 

Includes circuit board, stepping motor 

and all parts except 12 Vdc power 

supply. CAT* SMKIT $18.00 each 

METRONOME KIT 



frwjJflr 



-J£> 



This simple device can be set to click 
from 20 to 1.000 beats per minute. 
Easy to build, includes circuit board, all 
components and instructions. Oper- 
ates on a 9 volt battery {not included). 
CAT* METRO 1375 each 



PHOTO RESISTOR 



1 .000 ohms bright light. £© 
16K ohms dark. ifl 

0.1B2-dia, X .OS-high. 0.1 S" long leads. 

CAT*PBE-7 2 lor $1.00 

100 lor $45,00 • 1000 lor $400.00 



ORDER TOLL FREE 1-800-826-5432 



FAX (81 8) 781 -2653 • INFORMATION (81 8) 904-0524 

Call Or Write For Our 




Free 64 Page Catalog 

Outside the U.S.A. send $2.00 
postage for a catalog. 



Minimum Order $10.00 • All Orders Can Be Charged To Visa, Mastercard 

Or Discovercard • Checks and Money Orders Accepted By Mai! • California, Add 

Sales Tax • Shipping And Handling $3.50 for the 48 Continental United States - 

All Others Including Alaska, Hawaii, P.R. And Canada Must Pay Full Shipping • 

Quantities Limited • No COD. • Prices Subject to change without notice. 



MAIL ORDERS TO: ALL ELECTRONICS CORP • P.O. BOX 567 • VAN NUYS, CA 91408 



CIRCLE 107 ON FREE INFORMATION CARD 



Winning Products a 

Test/Measurement and Prototype Equipment 



51-Piece Electronic Tool Kit 



Global Specialties Proioboard Desic 



Tools Included in Kit: 

• 10' measuring tape 

■ 5,25" needle nose pliers 

• Electric tape 

■ Utility components box 

• 6 piece precision 
screwdriver sel 

■ 6" long tweezers 

■ 8 piece he* key wrench set 

■ 7" brush and scraper 

■ Digital Multimeter 

■ Brush 

• T tire point probe 

• Round needle lil e 

• to piece screwdriver set: 
S Slotted £ 4 Phillips 

■ 7" slotted probe 

■ Flat needle lile 

■ 4.5' diagonal cutting pliers 

MS305 




24HOUT. 



[^151 



6" adjustable wrench 
30 Wall soldering iron 
5.5" Stainless sleel 
scissors 
Soldering stand 
Rosin core solder 



5.25" Flat nose pliers 
Utility knife with extra blade 
Desoldering pump 
5.25" Beni needle nose pliers 
■ Carrying case: 
17.63"Wx12.5-Dk3.5"H 



592- : 



Features: 

• Ideal for analog, digital and microprocessor 
circuits 

• Triple DC regulated power supplies. +5V. 
+15V, -15V 

• S logic indicators 

■ Function generator with sine, square, 
triangle and TTL waveforms 




■ Two debounced push-button swilche: 

■ Two SPDT slide switches, all leads 
available and uncommited 

• A total of 2520 uncommited tie-points 

• Potentiometers: one 1 Ku and one 1 

■ Includes power supply, instrumental!! 
and bfeadboardi ng 



Jameco Logic Pulser Jameco Logic Probe 



$119.95 PB503 $29' 





■ Compalible with TTL. DTL. RTL. HTL. ■ Max Frequency 8QMHz » Minimum detectable 

HNIL MOS and CMOS ICs. * 1M£I Sync pulse: 10ns - 120K12 inpul impedance ■ Max. 

input impedance * Pulser mode ouipul supply vgilage: 25V * TTL threshold [Lot -0.8V 

current: 10mA ■ Square wave curfenl I -0.1V (Hi) ,2.3V -G-2V • CMOS threshold: 

output: 5mA ■ Audible lune ' I Lot 30% VCC '10% (Hi) 70%VCC 10% 



Soldering and Desoldering Stations 

60 Watt Analog Display Soldering Station ■ Electronic 

temperature control trom 200- to 878 F ■ Cartridge heat- 
ing element for a longer life of the soldering tip 

XY1683. ....$69.95 



30 Watt Electronic Temperature Controlled Desoldering 
Station - Electronic temperature control from 212 to 
842 F ■ Self contained high rotary vacuum pump 




LP540. 



.$16.95 MS104 $24.95 XY999 $299.95 



Prototype Products 

Jameco Solderless Breadboards 

-CXs 



Dirt- CoiUiT:: Binding 

L"x.W Poims Posts Price 



Metex Digital Multimeters A.R.T. EPROM Programmer 



General Specs - 

' Handheld, high 
accuracy * AC DC 

voltage. AC DC 
currenl. resistance, 
diodes. Continuity, 
transistor nFE 
■ Mannar ranging w 
overload protection 



M3650 & M4650 only: 

* Also measure frequency and capacitance 



M4650 only: ■ Data hold swaieh ■ 4.5 dtgii 




JE21 


3 25 i 2.125 


JE23 


6.5 1 2 125 


JE24 


6.5 1 3 125 


JE25 


6.5 1 4 25 


JE26 


5,875 1 5.75 


JE27 


7.25 « 7.5 



JfJO 


S 


S4.95 


830 





S6.95 


1 360 


2 


$12.95 


1.660 


3 


S17.95 


2. 390 


4 


$22.95 


3.220 


4 


$32.95 



M3610 

M365D 



M4650 



3 5 Digit Mullimelet S59.95 

3 5 Digit Multriele* w Frequency & 

.. i ::;■:: ':;'■::,; .......,....$74.95 

4 5 Uigii w Frequency Capacitance 

and Data Hold Switch $99,95 



■ Programs all currenl EPROMs in the 271 6 to 
37512 range plus the XZB64 EEPROM 
• RS232 port • Sollware included 

EPP $199.95 



UVP EPROM Eraser 



• Erases all EPROIWs ■ Erases 1 chip 

15 minutes and 8 chips in 21 min 
■ UV intensity: 6800 UW.'CM 2 



DE4. 



.$89 



EPROMs - for your programming needs 



Part No. 



Price Part No. 



J AMECO 



g 24 Hour Order Hotline 

o 

EC 



(415)592-8097 



o 

LU 
—I 
Lit 

o 

Q 
< 
rr 

92 



WS4 



MMC 



<£&> 



Please 
reler lo 
Mail Key 2 
when 
ordermrj 



Handheld Multimeter 



■ 3 5 digil LCD with autc-matfc polarity indication 

* AC- DC voltage measurement up to 500 wjlls 
" AC DC currenl measurement up to 200mA 

* Resistance measurement op to 2QMii - Con- 
tinuity checker with audible tone * Diode and 
logic tester « Au to manual range and dala hold 
functions « AH range protection and function in- 
dications 

DMM905 $39.95 



TMS2516 

TMS2532-35 

TMS2532A 

TMS2564 

TMS2716 

1702A 

2708 

2716 

2716-1 

27C16 

2732 

2732A-20 

2732A-25 

2732A-45 

27C32 



$4.25 
9.95 
7.95 
5.95 
5.95 
3.95 
4.95 
3.49 
3,95 
4.25 
4.95 
4.95 
3.49 
2.95 
4.95 



2764-20 

2764-25 

2764-45 

2764A-20 

2764A-25 

27C64-15 

27C64-25 

271280TP 

27128-20 

27128-25 

27128A-15 

27128A-20 

27128A-25 

27C128-15 

27C1 28-25 



Price 


Part No. 


1 


$3.95 


272560TP 


$ 


3.75 


27256-15 




3.49 


27256-20 




3.95 


27256-25 




3.25 


27C256-15 




3.95 


27C256-20 




3.25 


27C256-25 




2.95 


2751 20TP 




6.95 


27512-20 




7.95 


2751 2-25 




5.95 


27C512-15 




4.49 


27C512-20 




3.75 


27C512-25 




5.95 


27C010-15 


1 


7,95 


68766-35 





Partial Listing ■ Over 4000 Electronic and Computer Components in Stock! 



CIRCLE 114 ON FREE INFORMATION CARD 



Competitive Prices 

Computer Products and Electronic Components 



Assemble Your own Computer Kit! 

Jameco 16MHz 80386SX Desktop Computer Kit 

> Building your own computer provides you with a better understanding of 

components and their to notions 
1 In-depth assembly instructions included 
Have your new computer assembled and running in an evening, 
using common tools 
Soltware included 
Purchase computer kits configured by Jameco or design your own 



J AMECO 

^^ ELECTRONIC COMPONENTS 



COMPUTER PRODUCTS 

24 Hour Order Hotline (41 5) 592-8097 



* 7 nf 



Jameco 16MHz 80386SX 
Desktop Computer Kit 

Includes: 

■ 80386SX Motherboard with 
2MB RAM (expandable to 8MB) 

■ 101 -key enhanced keyboard 
-Multi I/O Card 

• Toshiba 1 ,44MB, 3.5" DSHD 
floppy disk drive 

• Baby sized desktop case 

• 200 Watt power supply 

• DR DOS 5,0 by Digital 
Research and AMI 
diagnostic software 







Relisys14" VGA 
Color Monitor 




• Max resolution: 720 x 480 
■ Bandwidth: 30MHz 

* Input: D815-pin (analog) 

RE9513 $399.95 

Jameco 16-bit Super 
VGA Card 



■ Emulates VGA. EGA. CGA, MDA and 
Hercules modes ■ Comes with 512K8 
video RAM upgradable to 1MB (Four 
514256-801 ■ Capable ol 1024 x 763 with 
256 colors (1MB video RAM lequiredl 

JE1058S $229,95 



Integrated Circuits 



Part No. 


1-9 


10+ 


Part No. 


1-9 


10+ 


7400 


S.29 


S.19 


7472 


$1.95 


S1.75 


7402 


.29 


.19 


7473 


.45 


.35 


7404 


,29 


.19 


7474 


.39 


.29 


7405 


,35 


.25 


7475 


.49 


.39 


7406 


.39 


.29 


7476 


.45 


.35 


7407 


.39 


.29 


7483 


.69 


.59 


740B 


.35 


.25 


7486 


.45 


.35 


7410 


.29 


.19 


7489 


2.95 


2.75 


7411 


.35 


.25 


7490 


.49 


.39 


7414 


.35 


.25 


7493 


.45 


.35 


7417 


.35 


.25 


74116 


1.19 


1.09 


7420 


.29 


.19 


74121 


.49 


.39 


7427 


.35 


,25 


74123 


.49 


.39 


7430 


.35 


,25 


74125 


.49 


.39 


7432 


.39 


.29 


74151 


.39 


.29 


7438 


.45 


.35 


74160 


.59 


.49 


7442 


.49 


.39 


74161 


.69 


.59 


7445 


.75 


,65 


74192 


.79 


.69 


7446 


.89 


.79 


74193 


.79 


.69 


7447 


.89 


,79 


74194 


1.19 


1.09 



Miscellaneous Components 

Potentiometers 

Values available (insert ohms into space marked "XX"): 

500U. 1K.5K. 10K,20K.50K, 100K, 1MEG 

43PXX *n Watt, 15 Turn $.99 

63PXX 'p Watt, 1 Turn $.89 

Transistors And Diodes 

PN2222 $.12 1N4735 $.25;2N4401 $.15 

PN2907. 12 2N3904 12J1N4148 07 

1N4004 10 1N751 15J2N3055 69 

2N2222A 25 C106B1 59HN270 25 

Switches 

JMT1 23 SPDT, On-On (Toggle) $1 .25 

206-8 SPST. 16 pin (DIP) - $109 

MPC121 SPDT.OnOtfOi (Toggle) $1 .19 

MS102 SPST. Momentary (Push-Bulton) $.39 



D-Sub Connectors and Hoods 
DB25P Male. 25-pin $.65|DB25H Hood $.39 

DB25S Female. 25-pin... $.75 1 




Hard 
Drives 



Conner (16-bit IDE) 

C P3044 40MB 3.5' Low Pintle $339.95 

CP3184 60MB35-HH... .$599.95 

CP3104 100MB 3i"HH ,.....$649.95 

ADP20 Hosl Adapter $29.95 

Look to Jameco 

• Wide selection of integrated 
circuits and components 

■ Quality prototype and test 
equipment 

■ Computer kits and accessories 

Additional items that Jameco offers: 

Tools 

Cables 

Connectors 

Data Books 

Motherboards 

Memory 

Math Coprocessors 

Computer Accessories 

Power Protection Equipment 

Much, much more ! 

Let us show you what we have to offer; 
call or write lor the latest Jameco catalog! 



4164-100 
4164-120 
4164-150 
41256-60 
41256-80 



Dynamic RAMs 

100ns. WK n $1.95 41256-100 

1.89 

1.99 

2.75 

2.49 



XC209R Ti 
XC556GT1 



LEDs 

(Red) $.14 XC556R 

4. (Green! ...16 XC556Y 
IC Sockets 



T1 3 .' 



(Red) ...$.12 

, (Yellow)... 16 



$50.00 Minimum Order 

Data Sheets - 50c each 

Call lor a FREE So.page catalog 1 . 

B 1991 Jameco Electronics 9J91 
CA Residents Add 

6.00%. 6.50% or 7.00% Sales Tax 
Shipping, handling and insurance are additional. 
(Costs may vary accofdi ng to wsipiis and shipping nuecnoc I 
Terms: Prices subieci to change without notice. 
Items subject to availability and prior sate. 
CompSele Irs! pi lerms wainnsiin is available upon readiest 
IBM * ■ ng41eraa FM«nu> or ^r«4«tui«tfc" Buiiitftti Matmr*! 



J AMECO 

^^ ELECTRONIC COMPONENTS 
COMPUTER PRODUCTS 

FAX: (415) 592-2503 
(415) 595-2664 
1355 Shoreway Road 
Belmont, CA 94002 

■ Customer Service -Technical Assistance • Credit Department ■ AH Other Inquiries ■ (41 5) 592-8097 • 7AM - 4PM P.S.T, 

CIRCLE 114 ON FREE INFORMATION CARD 



120ns. S4K I 1 
150ns. WK t 1 
Mliis. 2SSK x 1 
SUns. 255K 1 1 



100ns. 256Kii $1.99 
41256-120 120ns. 2S6K n 1.89 
41256-150 i50n 5 256Kst 
511000P-8DBfjns. 1MB it 
511000P-10 toons. 1MB m 



1.85 
7.95 
6.95 



• Call tor a complete listing ot IC's 



Low Profile 

8LP 

14LP 

16LP 

24LP 

2BLP. 

40LP 



Wire Wrap (Gold) Level #2 

8WW $.49 

14 WW 69 

16WW 79 

24WW 1.15 

2BWW 1.39 

40WW 1.89 

Soldertail Standard & Header Plug Sockets Also Available 



.$.11 
...12 
...13 
...19 

... .22 
... .28 



93 




LWICORN 

ELECTRONICS 

10010 Canoga Ave., Unit B-8 
Chatsworth. CA 91311 



SINCE 1983 — YOUR I.C. SOURCE — AND MUCH MORE!! 

NO SHIPPING CHARGES ON PRE-PAID ORDERS!* 

NO CREDIT CARD SURCHARGE! 

SCHOOL P.O.'s WELCOME! 



LASER DIODES 



Dynamic RAMS 



EPROMS 



STOCK * MFG 



LS9220 


TOSHIBA 


LS9200 


TOSHIBA 


LS9201 


TOSHIBA 


LS9211 


TOSHIBA 


LS9215 


TOSHIBA 


LS320D 


NEC 


LS022 


SHARP 



WAVE- 
LENGTH 
660 nm 

670 nm 
670 nm 
670 nm 

670 nm 
670 nm 
780 nm 



OUTPUT OPER. 
POWER CURR. 



OPEH. PHICE 
VOLT. 



3mW 

3mW 

5mW 

5mW 

10 mW 

3mW 

SmW 



85 mA 
BSmA 

613 mA 
SO mA 
IS mA 
85 mA 
65 mA 



2.5V 
2.3V 
2.4v 
2.3* 
2.4* 
2.2V 
1.75V 



129.99 
49.99 
59.99 
69.99 

109.99 
79.99 
19.99 



LASER TUBES 



STOCK* 

41256-60 

412S6-S0 

41256-100 

41256-120 

41256-150 

511000-70 

511000-80 

511DOO-10 

514256-70 

5 14256-80 

514256-10 

541000-80 

544256-80 



DESC. 

256K.S 1 
256KI1 
266K x 1 
256K i 1 
256K J 1 
1 meg x 1 
1 meg x 1 
1 meg x 1 
256K * 4 
256K i 4 
256K i 4 
4 meg x 1 
1 iriL-t; x 4 



SPEED 

60 ns 
60 ns 
100 ns 
1 20 ns 
150 ns 
70 ns 
80 ns 
100 ns 
70 ns 
80 ni 
100 ns 
80 ns 

8o m 



1-24 
2-59 
2.19 
1.99 
1.89 
1.79 
5.49 
5.29 
5.09 
6.49 
6.09 
5.89 
26.99 
31.99 



25-99 
2.46 
2.0S 
1.89 
1.80 
1.70 
5.22 
5.05 
4.64 
6.17 
S.79 
5.41 
25.64 
30.39 



100+ 
2.21 
1.87 
1.70 
1.62 
1.53 
4,70 
4.53 
4.36 
5.55 
5.21 
4.67 
23.08 
27.35 



STOCK* 

2716 

2732 

2732A 

2764 

2764A 

27128 

27C128 

27256 

27C256 

27S12 

27C512 

27C1024 

27 C 204 8 



SPEED 
450 ns 
450 ns 
250 ns 
250 ns 
250 ns 
250 ns 
250 ns 
250 ns 
250 ns 
250 ns 
250 ns 
200 ns 
200 ns 



1-24 25-99 
3.29 3.13 



4,19 
3,29 
3.49 
3.09 
4.79 
4.79 
4.59 
4.29 
5.49 
5.49 



3.98 
3.13 
3.32 
2.94 
4.55 
4.55 
4.36 
4.08 
5.22 
5.22 



10.99 10.44 
21.99 20.89 



100+ 
2.82 
3,58 
292 
2.99 
2.65 
4.10 
4.10 
3.92 
3.67 
4.70 
4.70 
9.40 
18.80 



STOCK * WAVELENGTH OUTPUT 
POWER 
(MIN) 



OUTPUT BEAM 
POWER DIAM. 
(MAX.) 



BEAM 
OIVERG. 



POLARI- OPERATING OPER. FIRING 
ZATION VOLTAGE CURR. VOLT. 



LT7770 

LT7650 

LT7556 

LT7655 

LT7655S 

LT7632 

LT7621S 

LT7634 

LT7621MM 

LT7627 

LT7628 

LT7627MM 



543 nm (Green) 
632 .flnm (Red) 
532 .Bnm (Red J 
632.Snm (Red) 
632.Snm (Red) 
632.8nm (Red) 
632.8nm (Red) 
632.8nm (Red) 
632.8nm (Red) 
632.8nm (Red) 
632.8nm (Red) 
632-Snm (Red) 



O.SmW 
0.5 mW 
O.SmW 
0.5 mW 
1.0mW 
IjmW 
2.0mW 
2.0mW 
5,0mW 
S.OmW 
S.omW 
10mW 



1.0m W 
2.0mW 
2,0mW 
2.0mW 
2,0mW 
30mW 
S.OmW 
S.OmW 
15mW 
15mW 
ISmW 
30mW 



071mm 

0.49 mm 

0.34 mm 

0.49mm 

0.49mm 

0.61mm 

0.75mm 

0.75mm 

1.0mm 

0.80mm 

0.80mm 

1.2 mm 



i 1.2 mrad 
£ 1.7 mrad 

< 2.4 mrad 
S 1.7 mrad 
£ 1.7 mrad 

< 3.0 mrad 
£ 1.2 mrad 

< 1 .2 mrad 
£ 2.5 mrad 

< 1 1 mrad 
£ 1.1 mrad 

< 4.0 mrad 



random 
>!00:1 

random 
random 
random 
random 
random 
>500:1 
random 
random 
>500 1 
random 



•75Du: 
lOOOv- 

i050v: 

lOOOv^ 
lOOOv^ 

1300^ : 
1300^: 

1250*: 
I900v; 
1900*: 
17S0v: 



110v 
100V 
100v 
100V 

100k 

IOOv 
100v 
IOOv 
100v 
IOOv 
100v 
IOOv 



6.SmA 
3.5 mA 
2.8 mA 
3.5 mA 
3,5 mA 
3.5 mA 
5.0 mA 
5.0 mA 
6.5 mA 
6.5 mA 
6,5 mA 
6.5 mA 



< 8kV 

< 7kV 

< 8kV 
£ 7kV 

< 7kV 
£ 7kV 

< 7 kV 
£ 7kV 
£ 7 KV 

< SkV 

< 8kV 
<, :-: ■■:■; 



MIN. 
SERIES 

RES. 

81k a 
68k n 

82k n 
68k 
68k n 

Bikn 

68k n 

E8k n 

68k n 

Blk n 

■?,■: n 
sik n 



SIZE WT. 

DXL (GM.( 

(IN MM) 



37x350 

25x146 

22.5 x 1 18 

25 X 150 

25x150 

20x210 

30x255 

30x255 

30x255 

37x350 

37x350 

37 x 350 



200 
70 

80 
70 

,'!.: 

70 

140 

140 

140 

200 

200 

200 



BRH 
CL. 

II 

Ilia 
Ilia 
Ilia 

life 
Ilia 
Ilia 
Ilia 

1: 13 
lllb 
lilb 
lllb 



PRICE 
1-9 

799.99 
529.99 
134.99 
144.99 
159.99 
249.99 
204.99 
209.99 
359.99 
369.99 
389.99 
479.99 



749.99 
479.99 
124.99 
134 99 
144.99 
229.99 
191.99 
194.99 
334.99 
344.99 
384.99 
444.99 



Laser Pointer 



• Output: 3,5 mW 

• Wavelength: 670NM 

■ Power Supply: 2xAAA Batteries 
(included) 

■ Beam: Appro*. 3" @ 100 yards 
Quantity Discounts Available 
STOCK # PRICE 
LSPOiNT $199.99 



Power Supply 



♦" 



Input: 11 5/230 V 
. Output: +5v @ 3.75A 
+12v@ 1.5A 
-12v@ .4A 

■ Size: 7" L x 5V," W x 2W H 



STOCK » 
PS1003 



PRICE 

S19.99 



Collimator Pen 




■ Output: 2.5 mW (max.) 

• Current: 90-150 mA 

• Op. Volt.: 2.2-2. 5V 

■ Wavelength: 820NM 

■ Data Sheet inc. 



STOCK # 
SB 1052 



PRICE 
$39.99 



Disc Drive & Computer 
Cleaning Kit 




Nol just a drive cleaner-but a complete 
computer cleaning kit. includes sv*abs, 
head cleaning fluid, anti-static cleaner, 
screen wipes and cleaning di Skene. 

STOCK # PRICE 

SB1099 3Vs" Kit $6.99 
SB1100 5VV Kit $6.99 



Disc Drive Head- 
Cleaning Kit c _ 



Anti-Static 
Screen Wipes 



Robotic Arm Kit 





Avoider Robot Kit 



Includes cleaning fluid and 
head-cleaning diskette 

STOCK # PRICE 

SB 1105 3Vs" Drive Kit $1.99 
SB1106 5V." Drive Kit $1.99 



For static-sensitive app&jcalions. 
Dispenser packs, individually wrapped. 

STOCKS PRICE 

S81104 Dispenser pack S1.99 

of 25 wipes 
$61107 Dispenser pack $4.99 

of 100 wipes 



Robots were unco ccmlined to science taction 
movi» Today. whetlwlhe^Ve performing 
cangerotis tasks or putting together complex 
products robolics are iindtng their way nto 
more and more industries. The Robotic Arm 
K'E is an educational hit that teaches basic 
robot.c arm fundamentals as well as tasting 
your awn molar skills. Command n 10 periorm 
simple tasks 



s% 



An intelligent robot (hat knows how 
io avoid hitting walls This robot 
emits an infra-red beam which 
delects an obstacle in front and 
then automatically turns ieft and 
continues on. 



STOCK # 

Y01 



PRICE 

$49.99 



STOCK # 
MV912 



PRICE 
$49.99 



o 

o 
BE 

b 



LU 

6 

Q 



ORDER LINE — (800) 824-3432 



INTERNATIONAL ORDERS — (818) 341-8833 
FAX ORDERS — (818) 998-7975 



6 TECHNICAL SUPPORT — (818) 341-8833 



CIRCLE 185 ON FREE INFORMATION CARD 






• 15.00 MINIMUM ORDER 

• UPS BLUE. RED & FEDERAL EXPRESS 
SHIPPING AVAILABLE 

• OPEN MON-FRI 9:00 AM - 6:00 PM. 
SAT 1 0:00 AH - 3:00 PM POT 

• CA RESIDENTS ADD 7°, SALES TAX 

• CALL FOR QUANTITY DISCOUNTS 

• CALL FOR FREE CATALOG 

(FOR 1ST CLASS DELIVERY OR CATALOGS 
DELIVERED OUTSIDE THE U.S. — SEND $2.00) 

• WE CARRY A COMPLETE LINE OF ELECTRONIC 
COMPONENTS 

■NO SHIPPING CHARGES ON PRE-PAID 
ORDERS DELIVERED IN THE CONTINENTAL U.S. 



94 



FAX DIRECT 
1-800-582-1255 



WCH 



ORDER DIRECT 
1-800-582-4044 



j VHF - UHF RF TRANSISTORS" ~] 



Output 



Input Frequency Gain 



Or der # Price Pwr. (W) Pwr. (W} Range (Mhz) db.' Mhz 'Packaga 



MRF221 

MRF237 

MRF238 

MRF240 

MRF240A 

MHF247 

MRF260 

MRF262 

MHF317 

MRF321 

MHF340 

MRF401 

MRF406 

MRF422 

MRF426 

MRF427 

MRF428 

MRF450A 

MRF455A 

MRF45B 

MRF51S 

MRF555 

MRF559 

MRF607 

MRF641 

MRF646 

MRF6S2 

MRF654 

MRF660 

2N3866 

2N4427 

2NS641 

2N5642 

2NSS43 

2N5944 

2N5945 

2N5946 

2N6080 

2N60S1 

2N60B2 

2N6083 



16.35 

3.69 

15.95 

17.49 

17.49 

24.75 

11.95 

12.95 

64.95 

24.95 

9.95 

13.49 

14.99 

35.95 

19.49 

16.95 

59.95 

14.49 

12.69 

19.95 

2.95 

3.49 

2.25 

2.49 

20.49 

25.95 

11.49 

19.95 

13.95 

1.25 

1.25 

16.95 

18.49 

19.95 

11.95 

11.95 

14.95 

9.89 

11.95 

14.95 

14.95 



15 3.5 136-174 6.3/175 211-07 

4 0.25 136-174 12/175 79-05 

30 3.7 136-174 9/175 145A-09 

40 5 136-174 9/175 145A-09 

40 5 1 36-1 74 9/175 21 1-07 

75 15 136-174 7/175 316-01 

5 0.5 1 36-174 1 0/175 221 A-04 

15 3.5 136-174 6.3/175 221 A-04 

100 12.5 30-200 9/150 316-01 

10 0.62 100-500 12/400 244-04 

8 0.4 30-200 1 3/136 221 A-04 

25 (PEP/CW).. 1,25 2-30 13/30 145A-09 

20 [PEP/CW).. 1.25 2-30 12/30 211-07 

150 (PEP/CW) ...15 2-30 10/30. 211-11 

25 (PEP/CW) ..0,1 6 2-30 22/30 21 1 -07 

25 (PEP/CW) .-0.4 2-30 18/30 21 1 -1 1 

150 (PEP/CW) ..7.5 2-30 13/30 211-11 

50 4 14-30 1 1/30 145A-09 

60 .3 14-30 13/30 1 45A-09 

80 5 14-30 12/30 21 1-11 

0.75 0.12 400-512 8/470 79-04 

1.5 0.15 400-512 10/470 317D-02 

0.5 0.08 806-960 8/870 317-01 

1.75 0,12 136-174 11.5/175 79-04 

15 2,5 400-512 7.8/470 316-01 

40 13.3 400-512 4.8/470 316-01 

5 0,5 400-512 10/512 244-04 

15 2.5,. 400-512 7.8/470 244-04 

7 2 400-512 5.4/470 221 A-04 

1 0,1 100-400 10/400 79-04 

1 0.1 136-174 10/175 ....79-04 

7 1 30-200 .......8.4/175 144B-05 

20 .....3 30-200 8.2/175 145A-09 

40 6.9 ............30-200 7.6/175 ...145A-09 

2 0.25 400-512 S/470 244-04 

4 0.64 400-512 8/470 244-04 

10 2.5 400-512 6/470 244-04 

4 0,25 136-174 12/175 145A-09 

15 3,5 136-174 6.3/175 145A-09 

25 ...6 136-174 6.2/175 145A-09 

30 8.1 136-174 5.7/175 145A-09 

"Complete dimensions, pin-outs and pictures of all packages are contained in 

Motorola's RF Device Databooks (See Right). 



Order # Price Description 



Pins 



5719 

8362R8 

8364R7 

8372A 

8520A 

315093-02 



17.95 
39.95 
37.95 
99.95 
16.95 
34.95 



Gary [8386) 48 

Denise "Half Bright" (252126-02) 43 

Paula (2521 27-02) 48 

Farter Agnus (1MB) For A50Q/A20Q0 (318069-02) PLCC 84 

Complex Interface Adapler For ASOO/AUDOO (318029-03) 48 

KickstartROM1.3 40 



'NOTE: No data available on Amiga computer chips 



■Dimensions: 1.187" s .95" >: .735" 
■Cross To: P&B' R1 series 
-Mounting: Solder terminals 



'P&B p Poller & Brumfleld 

Order # 1-9 10+ Description 



Coll 
Res. 



R185-3 
R185-7 



6.99 5.99 
7,99 6.99 



Relay 1 2Vdc 

Relay 12Vdc 



.18511 

.1B5S2 



Contact 
patina Contact 

3A DPTD 

7.5A DPTD 




CH.22 


.89 


CH.39 


.89 


CH.32 


.89 


CH1.0 


.89 


CH2.2 


1.09 


CH4.7 


1.09 


CH6.8 


1.49 


CH10 


1.49 


CH22 


1.49 



.79.. 

.79.. 

.79.. 

.79.. 

.99.. 

.99. 
1.39.. 
1.39. 
1.39. 



Freq. 


Resist. (DC) 


Indue! 




0.1 4C1 


935mA 




0.3CS1 


640mA 



...0.22 

.0.39 

...0.82 25Mt« 0.8511 380mA 

...1.00 25Mhz I.0DS 350mA 

...2.20 7 9Mhi 0.4011 550mA 

...4.70 7.9Mhz 1.2011..... 320mA 

...6.80 7.9Mhz.. 2,000. 245mA 

10 7.9Mhz 3.7015. 180mA 

22 2.5Mhz 3.30U 190mA 



1.49 1.39 47 2.5Mnz 4S0n 165mA 



miMMWMtiMteMi 




RF Device Data - Volumes 1 & 2 

This rwo volume set contains over 2200 pages of dala on RF Power 
TWOS FETs, RF Power Bipolar Transistors, RF Small Signal 
Transistors, Tuning and Switching Diodes, and RF Amplifiers, Also 
included are drawings, diagrams, dimensions and pin-outs on all 
packages. 

Order jf DL1 10 1 4.95 RF Device Vol. 1 & 2 Weight: 4.25 lbs. 

Telecommunications Device Data 

Almost 900 pages covering Switching, Integrated Voice/Data, Modem. Filter. Dala 
Communication, Basic Phone. Cordless Phone, Transmission and RF Modem Circuits, 

Order#DL136 11.95 Telecommunications Device Data Weight: 1.75 lbs. 

MPU/MCU/Peripharal Data - Volumes 1 & 2 

Over 2300 pages on Motorola's Microcontroller and Microprocessor families such as the 
MC6300. MC6802, MC6S21, MC6846, MC146813. MC68701, MC68705, etc. 

Order # DL139 16.95 MPU/MCU/Peripheral Data- Vol. 1 & 2 Weight: 4 lbs. 



CK MOUNT CABIN 



A range ol ventilated 19" rack mount 
cabinets, designed to accept DIN 41494, 
IEC 297. EIA RS-310 C-1977 and JIS 
C601 0-1969 Classic and contemporary 
styling, black hi-gloss finish, together with 
innovative techniques result in a ruggedly 
built stylish enclosure. The cases are 
supplied flat packed and are easy to 
assemble. 
Order* 1-9 10+ Panel (mm'in) 




E3120E 



E3120C 



Cabinet (HxWxD mm/In) Handle Weight 



E3120A 36.95 34.95 4S0i19.2'*«'1.7r 38'1.5-*«J/16.7"lZ44r9.S- - 6.5 lbs. 

E3120B 44.96 42.95 4Srj,'19.2 - x B7/3.4S - B3/3.3Z - x 424/1 6.7" x £44*3.6* 67/2.68".. 7.7 lbs. 

E3120C 49.95 47.95 4B0,'19.2" ■ B7/3.4S- .S3V3.32" J 424/16.7-* Wa'13.32" ....57S.W 9.02 lbs. 

E3120D 54.95 52.95 480/t9.2" x )32/5.ZS"..,122/4.Ba" I 424,'IS.r I424/I6.r..-..9S73.92' 10.12 lbs 

E3120E 59.95 57.95 460.192" x 177.708" 172^Bfl" x 424/16 7"x333/13.32"„..13& ! 5.44",...10.7S It 



3TEEL ENCLO 

FEATURES 

♦Ventilation holes 

■Self-adhesive feet included 

-From 5 rear panels: 1.3 mm aluminum alodine 

(painted white) 
■Top & bottom covers: 0.9 mm phosphated sleet 

(painted black: 

Order # 1-9 10+ Pes or i pt ion Pi me ns to ns (Hx Wx D ) 




E3119A 


12.95 


11.95 


E3119B 


15.95 


14.95 


E3119F 


19.95 


18.95 


E3119G 


13.95 


12.95 


E3119K 


24.95 


23.95 


E3119P 


29.95 


28,95 



Steel Enclosure 2.5"x8" x 7" 2. 64 lbs. 

Steel Enclosure 2.5" x 12" x 7" 3.74 lbs. 

Steel Enclosure 2.5" x 1 7" x 1 1" 6.82 lbs. 

Steel Enclosure 3.5" x 8" x 7" 2.86 lbs. 

Steel Enclosure 3.5" x 17" x 11" 7.26 lbs. 

Steel Enclosure 5.2" x 17" x 11" 7.70 lbs. 

E >yiech 




2917 Bayview Drive 
Fremont, CA 94538 



Order Direct: 1 
Fax Direct: 1 



■800-582-4044 
800-582-1255 



Monday- Friday, 7am - 5pm (PST)/10am-8pm (EST) 

_VJ COD-No personal checks, US funds ($5.00 Charge) 
ED USPS 



V ups V 



Federal Express IV I Airborne 

Add 5% of total for shipping UPS Ground ($3,00 min.). 
Actual shipping charges based on weight. 

Call or write today for your free copy of our 1 991 catalog. 

California residents, add appropriate sales tax. 

12 month warranty on all EasyTech products. 

30 day money back guarantee. 

We reserve the right to substitute manufacturers. 

Prices subject to change without notice. 



CIRCLE 181 ON FREE INFORMATION CARD 



W 

m 

TJ 

-I 

m 

oo 

m 

3] 



95 



SCIENTIFIC & ELECTRONIC 
PRODUCTS 



LASERS AND SCIENTIFIC DEVICES 

VRL2K 3mw His Red Laser Diode System Kit 5159.50 

LUSH Lassr Beam "B tunica" 1 Listener Kit S19S.50 

LHUK Visiule Simulated 3 Color laser Kit J44.50 

LC7 40 Will Burning Cutting Laser Plant S2Q.au 

RUB4 Hi Powered Pulsed Drilling Laser Plana S20.00 

LGU4Q I |D2mWHeWi Vis Red LaserGun Assembled ........5199-00 

LLS1 LiserLiteSlio«r-3 Methods Plans SZO.llu 

SD5K See in the Dark Kit S299.50 

EML1K Elecliomeanetic CDil Oun Kit S59.S0 

MCPI Hi Velocity Coil Gun Plans SIS. 00 

LEVI LeYllalino Deiriee Plana Sia 00 

EH1 Electronic Hypnotism TeohniQues Plans $10. DO 

HIGH VOLTAGE AND PLASMA DISPLAY DEVICES 

HVM7K 75.000 Volt DC Variable Output Lab Source Hit $149.50 

I OG3K I o I i R ay G i . i K il . 1 1 ru : a cl g n g ■■ y j .',' . i h : u I ■:: re s $69.50 

NIG9K 12V.-115 VAC Hi Out Neg Inn Generator Kit $34.50 

ErVtAlK ft I ikinel c i-nl'i n. ;■ I l.:::ln:: Man AssemBler) $99.50 

LG5K Lightning DisplayGlobeHIt S54.50 

BTC1K Worlds Smallest Tesla Coil Kit S49.50 

BTC3K 250KU Table Top ftsla Coil sit SZ49.50 

BTCS 1.5 Million Yells Tesla Coil Plans SZO.OO 

JL3 Jacahs Ladder -3 Models Plans $15.00 

GP.A1 Anil Gravity Generator Plans $10.00. 

PFS20 Plasma Fire Sailer Assembled $59.50 

DPL20 Dancing Plasma la Music and Sounds Assembled $79.50 

SECURITY AND PROTECTION DEVICES 

I TM 1 1 DO .00 Vo II I nil midalo r up 1 19" Assembled $129.50 

IPGTD Invisible Pain Field Blast Wave Gen Assembled $74.50 

PSP4K Phaser Sanic Blast Wave Pistol Kit $59 .51) 

LIST10 Infinity fcntr, lislen in Via Phone Assembled $199.50 

TAT30 Automatic Tel Recording Oevice Assembled $24.50 

VWPM7K 3 Ml. FM AuloTel Transmilter Kit $49 .50 

FMV1K 3M1.FM Voice Trans miller Kit $39.50 

HQD1K Homing/Tracking Beeper Transmitter Kil..... ...$49.50 

EAST OflOEHIHB PBOCEOUBE TOLL FBEE 1-SOO-22M705 

or 21 UBS OM t -603-673 -4730 or FM IT T0 1 -SOS -672-54(16 

VISA, 'rlt: CHECK. MO IN OS FUNDS. INCLUDE 10% SHIPPING. DROERS 

SIM JJ S UP ONLY ADD $10 00. CATALOG SI. 10 OR FREE WITH OB DEB. 



INFORMATION UNLIMITED 

P.O. BOX 716, DEPT. R3, AMHERST, NH 03031 



ADVERTISING INDEX 



THE ELECTRONIC GOLDMINE 



C/3 

o 



o 



o 

< 

LT 



96 




Th* Electronic 
GoHmk™* has one rJ Ihe J 

QfEfllESt KlKlJDIB Dl UriOJLB 

escclronic kits avatfafcte in 
ihe ftOfM! iVe hM 
Oter 65 kils and 
met 1.400 unique, 
bargaiii priced, ramponana 

■r OH Ci: jli.fi 1 



-AT^LObr 



IttPF ERtWT ! 



liVAC ADAPTER 

ftttJ CU 1?5VAC X. up ki 265 rru. Brand 
ntW. ftU imrf 2 (Wig (OTHlf txrwdzr grU 

lovj riwaij wftt. fa lUndaiTj 120 VAC 
G95D 11.39 .«12 10CVS1CB 



\j%® 



FISH CALLER KTT 




Thic Vt prodLjcB* ■ ekekhg isund when 
It uid to jfluct Ish Wi hm had 
axlaron *tu rw« reported exzolcrt 
Is' FijjJiitis very Cny Crtul bt-i'G 
jTKl ^Tijl Glycol KiSni a'lmati v/vJ' 
■r.cn ::a plaCOCl it a WolW "•.)"" 0' arc) 
■TrWed ri:- IThB wattr. OpfifauM Iram a 

■3V L-:.:iorv («* nciJd&d) 

C4S6Q W5D 



METAL LOCATOR KIT 





TCT1 

■)!'■' 



Oaioct corn, mga, burwd Inctaitjr*, 
Ate wffi nil iirpki >c buld > i. Trin- 

»lCriZKl EXCUt UHH UnrqLKI (JPiWiiClfi 
col, irrhtdhl if wand OTOCSf/ fje Top rjl 
PC b«nl 1r>« Mdn] I . cx-j fcr Ki1 
rtolocrs moljl win A shi*1 in t«H whctl 
q. iriBmfjd b a sLarWlafd pOftlHa 
AM ridia i'ioj sjL^ryl Optxaloi iron 
a 9V biLBv (ra ndiritxll 
C4515 $5-^S 



MICRO MINI 
HIGH VOLTAGE 
POWER SUPPLY 



9? 'Bit 



"_7T 



aflt in' 1GQW vrih ortrV 
Ci.'OC 4". L>awi orty (£ 

G99t S6.00 



INVERTER 
TRANSFORMER 

^rrrn i -t rj^ij 

! - ii"-i'::"r»}i 

ItH lt» win 555 

C r. i-y-,tn 

12VDC to 250/ In itrobttf 

hjor«Kvt Tdbos wKh 

tchtmalac. 

N17G3 £:.lO uch 



TINT 

RECTANGULAR 
SPEAKER 

TT« lit, | '" **fJ 
cpMkhdr « M 

raafirtw l a^ 

riCDchn -JL-t 

(Ticedareti and r.i/^ 
ic«jjf4> Trta! cast Gr-w" 
fcr JTlrnirtUtC np^Kalorn 

Sao w* si/ie,- * aw 

G9SS *1-0Q ioa$aa 




ULTRAVIOLET SENSOR 
SUN EXFOSURS METER 



— ^MM^ 



Snu'I oriicttTcot; dwn dalccl? 1jV (n*rm f"?" 1 Tv 

5LT^ and SWxIs Jl sy-ii wCnn yCm'vd hM nrlcLfijIi Bjt(JHCrni. 
H«5 2 il^i ror skin Ira grid sun scrrHn rung (SPP, UloS ,C 
craiiiy irJ ipsciai ijv »nsa. AsiwdilflfJ and wattf o utw, 
nc now cuipLs (am ri naw av&lafSti at a Sradion cf Ha ongnal 
com (BefiiftM W bflti«Y. kA ndudacr 1 i-^** u q* 



MINIMUM OHDEH: $10 00 p!u£ $3Su sfupping and ?unc!-ng 
Wet accept MO. Vgj and Money OnJerS- 

SEfJD ORDERS TO. TlTt? i' .:■!■■■< .. .'iOtUTWie 

P.O. Box 5408 ScoHKtiie. AZ 85261 

PHONE ORDERS (&Q2) 4&1'74$4 FAX ORDERS (602} 451-9495 



CIRCLE 182 ON FREE INFORMATION CARD 



RADIO-ELECTRONICS does not assume any responsibility for errors that may appear in 
the Index below. 



Free Information Number Page 

108 AMC Sales 39 

75 Ace Products 30 

107 All Electronics 93 

— Amazing Concepts 88, 96 

180 American Reliance Inc 30 

84 Appliance Service 30 

109 C&SSales 32 

— CIE , 7, 29 

— Cable Ready Company 84 

— Command Productions 75 

— Computer Book Club 73 

58 Cook's Institute 39 

127 Deco Industries 30 

181 EasyTech 95 

182 Electronic Goldmine 96 

— Electronics Book Club 8 

121 Fluke Manufacturing CV2 

— Fordham 3 

— Global Cable Network 83 

190 Cilobal Specialties 5 

— Grantham College 25 

86 Heathkit 14 

189 Hewlett Packard 15 

— HighText Publications, Inc 72 

— ISCET 87 

1 14 Jameco 92 

87 MCM Electronics... 85 

53 MD Electronics 86 

93 Mark V. Electronics 87 

1 17 Mouser 24 

— NRI Schools 21,81 

186 Optoelectronics CV3 

56 Parts Express 89 

— Perfect Cable 84 

177 R.L. Drake Co 31 

78 Radio Shack 23 

187 SCO Electronics 78 

— Scope Electronics 3 

176 Sencore CV4 

— Star Circuits 24 



92 Tektronix 13 

123 Test Probes 17 

— The SPEC-COM Journal 39 

185 Unicorn 94 

188 US Cable 78 

178,179 Viejo Publications 72, 75 

184 WFI' Publications 77 

191 Worldwide Cable 88 



ADVERTISING SALES OFFICE 

Gems back Publications, Inc. 
500 B Bi-County Blvd. 
Farmingdals. NY 11735 
1-C516) 293-3000 
President: Larry Steckler 

For Advertising ONLY 
516-203-3000 

Fax 1-516-293-3115 
Larry Steckler 

publisher 
Christina Estrada 

assistant to the President 
Arline Fish man 

advertising director 
Denise Haven 

advertising assistant 
Kelly McQuade 

credit manager 

Subscriber Customer Service 

1-800-288-0652 

Order Entry for New Subscribers 

1-80O-999-7139 

7:1X1 AM ■ 6:00 PM M-F MST 

SALES OFFICES 

EAST/SOUTHEAST 

Stanley Levttan, Eastern Sales Manager 

Radio-Electronics 

1 Overlook Ave. 

Great Neck, NY 11021 

1-516-487-9357, 1-516-293-3000 

Fa* 1-516-487-8402 

MIDWEST/Texas/Arkansas/Okla. 

Ralph Bergen, Midwest Sales Manager 

Radio-Electronics 

540 Frontage Road — Suite 204 

Northtield. IL 60093 

1-708-446-1444 

Fax 1-708-559-0562 

PACIFIC COAST/Mountain States 

Marvin Green, Pacific Sales Manager 

Radio-Electronics 

5430 Van Nuys Blvd. Suite 316 

Van Nuys. CA 91401 

1-81 B- 986- 2 001 

Fax 1-818-986-2009 

RE Shopper 

Joe Shore, National Representative 
P.O. Box 169 
Idyllwild, CA 92349 
1-714-659-9743 
Fax 1-714-659-2469 



MAXIMIZED SENSITIVI 

U We've Carefully balanced the amount of gain used in our input 

amplifiers - too much or too little results in poor performance. 
m OPTOELECTRONICS 1 HANDI-COUNTERS ' with maximized 

V^ sensitivity give you the maximum range for antenna pick-up. 

Made in the USA 




MODEL 3000 

Multi-function Counter 

10Hz-3GHz, 1 Digit LCD with 

frequency, period, ratio, interval 

& signal level bargraph....$375. 




Maximum 

Security 

Device. 

Increase your 

frequency 

finding™ by 10 

times the distance 
or more. 
Tunable 
Preselector 
APS-104 
$995. 

Counter Sold 
separately 



MODEL 8030 

With all the features of the 
3000 plus enhanced input 
signal conditioning and 
enhanced TCXO time base 
$579. 





S 



199 



The Original Pocket-Sized LED 

Handi-Counter™ 

All of OPTOELECTRONICS' LED 

Handi-Counters™ will: 
• Count frequencies above 2.4GHz. 
Have display saving Power Switch 

(avoids premature LED burn-out, leading cause of 
counter failure.) 

Accept no substitutes - 

Look for the OPTOELECTRONICS 

name on the label! 




J 



Model 2300- 1MHz-2.4GHzl 

Available with NiCads and AC 
Charger Adapter. Complete 
Package only.. ..$128. 



Only OPTOELECTRONICS 

offers you MAXIMIZED SENSITIVITY. 

1-800-327-5912 



Model 221 0A 

10Hz-2.4GHz Full range 
counter. Price includes 
Nicads & AC charger/adapter. 



Factory Direct Order Line 

FL{305)771 -2050 ' FAX(305)771 -2052 

5821 NE 14th Ave. • Ft. Lauderdale, FL33334 ■ 5% Ship/Handling (Max. $10) 
U.S. & Canada. 15% outside continental U.S.A. 
Visa and Master Card accepted 



CIRCLE 186 ON FREE INFORMATION CARD 



Introducing The Only Complete Solution 
For All Your Monitor Servicing Needs! 





CM2000 Computer MonitorAfll 



The Only Analyzer 
That Helps You 
Pinpoint Defects In 
All Computer 
Monitors! 



Patented - A Sencore Exclusive! 



Completely Test And Troubleshoot 
All High Resolution And MuIti-Scai 
Computer Monitors From The 
Input Connector To The CRT... 
Guaranteed! 



Here's What The CM200Q Offers You: 

• Complete High Resolution Computer Monitor Analyzing 

• Fully Programmable Scan Rate And Pixel Resolution 

• Innovative Performance Testing Patterns 

• Special Sync-Locked Substitution Signals 

• Patented "Ringer" Test To Dynamically Analyze All: 

• Yokes 

• IHVTs/Flybacks 

• Switching Transformers 

■ Integrated 2,000 DCV And P-P Meter 

■ Exclusive "Hook-up" Adapters Available For All Popular 
Monitors 

• Portable Troubleshooting For All Your Field Service Needs 



Call 1-800-SENCORE «t 70S 



(736-2673 circle i?s on free information card 3200 Sencore Drive, Sioux Falls, South Dakota 57107